

; ff^lg^ 


Plate 1. 


A MANUAL 


FOR THE 


STUDY OF INSECTS 

REVISED EDITION 


BY 


JOHN HENRY COMSTOCK 

Emeritus Professor of Entomology in Cornell University 


AND 


ANNA BOTSFORD COMSTOCK 

Emeritus Professor of Nature Study in Cornell University 


AND 


GLENN W. HERRICK 

Professor of Entomology in Cornell University 


tKtoenttetl) Ctottton 


ITHACA, NEW YORK 
THE COMSTOCK PUBLISHING COMPANY 

i93i 


Copyright, 189s, 

BY 

JOHN HENRY COMSTOCK 

Revised Edition 
Copyright, 1930, 

BY 

JOHN HENRY COMSTOCK; 


fey* *•* 

ilLIBRAR' 

PREFACE TO ORIGINAL EDITION 

For many years the most pressing demand of teachers and learners in 
entomology in this country has been for a handbook by means of which 
the names and relative affinities of insects may be determined in some 
such way as plants are classified by the aid of the well-known manuals 
of botany. But, as the science of entomology is still in its infancy, the 
preparation of such a handbook has been impossible. Excellent treatises 
on particular groups of insects have been published; but no general work 
including analytical keys to all the orders and families has appeared. It 
is to meet this need that this work has been prepared. 

The reader must not expect, however, to find that degree of complete- 
ness in this work which exists in the manuals of flowering plants. The 
number of species of insects is so great that a work including adequate 
descriptions of all those occurring in our fauna would rival in size one of 
the larger encyclopaedias. It is obvious that such a work is not what is 
needed by the teachers and students in our schools, even if it were pos- 
sible to prepare it. An elementary work on systematic entomology will 
always of necessity be restricted to a discussion of the characteristics of 
the orders and families, and descriptions of a few species as illustrations. 
Complete synopses of species will be appropriate only in works treating of 
limited groups. It is believed, therefore, that it would not be wise to 
materially change the scope of the present work even if it were possible 
to describe all of our species. 

Although much pains has been taken to render easy the classification 
of specimens, an effort has been made to give the mere determination of 
the names of insects a very subordinate place. The groups of insects 
have been fully characterized, so that their relative affinities may be 
learned; and much space has been given to accounts of the habits and 
transformations of the forms described. As the needs of agricultural 
students have been kept constantly in view, those species that are of 
economic importance have been described as fully as practicable, and 
particular attention has been given to descriptions of the methods of 
destroying those that are noxious, or of preventing their ravages. 

An effort has been made to simplify the study of insects as much as 
possible without sacrificing accuracy in the descriptions. Only such 
morphological terms have been used as were necessary to accomplish the 
object of the book in a satisfactory manner. And so far as possible a 
uniform nomenclature has been used for all orders of insects. The fact 
that writers on each order of insects have a peculiar nomenclature has 
been a serious obstacle to the progress of entomology; this is especially 
true as regards the nomenclature of the wing-veins. It has been neces- 
sary for the student in passing from the study of one order of insects to 
that of another to learn a new set of terms ; and in many cases writers on 
a single family have a peculiar nomenclature. 

The present writer has endeavored to remove this obstacle by making 
a serious study of the homologies of the wing-veins, and by applying the 


iv PREFACE TO ORIGINAL EDITION 

same term throughout the work to homologous veins. The result is that 
the student is required to learn only one set of terms; and in applying 
these terms there will be brought to his attention in a forcible manner the 
peculiar modifications of structure characteristic of each order of insects. 
Heretofore, with a different nomenclature for the wing-veins of each 
order such a comparative study of the various methods of specialization 
has been beyond the reach of any but the most advanced scholars. 

The principal features of the method of notation of wing-veins pro- 
posed by Josef Redtenbacher has been adopted. But as the writer's 
views regarding the structure of the wings of primitive insects are very 
different from those of Redtenbacher, the nomenclature proposed in this 
book is to a great extent original. The chief point of difference arises 
from the belief by the present writer that veins IV and VI do not exist 
in the Lepidoptera, Diptera, and Hymenoptera; and that, in those or- 
ders where they do exist, they are secondary developments. The reasons 
for this belief are set forth at length in my essay on Evolution and 
Taxonomy. 

In this essay there was proposed a new classification of the Lepidop- 
tera, which was the result of an effort to work out the phylogeny of the 
divisions of this order. This classification has been further elaborated in 
the present work. In the other orders but few changes have been made 
from the more generally accepted classifications. It is more than prob- 
able however, that when the taxonomic principles upon which this classi- 
fication of the Lepidoptera is based are applied to the classification of the 
other orders radical changes will be found to be necessary. 

A serious obstacle to the popularization of Natural History is the 
technical names that it is necessary to use. In order to reduce this diffi- 
culty to a minimum the pronunciation of all of the Latin terms used has 
been indicated, by dividing each into syllables and marking the accented 
syllable. In doing this the well-established rules for the division of Latin 
words into syllables have been followed. It seems necessary to state this 
fact in order to account for differences which exist between the pronunci- 
ations given here and some of those in certain large dictionaries recently 
published in this country. 

Nearly all of the wood-cuts have been engraved from nature by the 
Junior Author. As the skill which she has attained in this art has been 
acquired during the progress of the work on this book, some of 
the earlier-made illustrations do not fairly represent her present standing 
as an engraver. But it does not seem worth while to delay the appear- 
ance of the book in order to re-engrave these figures; especially as it is 
believed that they will not be found lacking in scientific accuracy. The 
generous appreciation which the best engravers have shown towards the 
greater part of the work leads us to hope that it will be welcomed as an 
important addition to entomological illustrations. 

Although the chief work of the Junior Author has been with the pencil 
and graver, many parts of the text arc from her pen. But in justice to 
her it should be said that the plan of the book was changed after she had 
finished her writing. It was intended at first to make the book of a much 
more elementary nature than it is in its final form. It has seemed best, 
however, to leave these parts as written in order that the work may be of 
interest to a wider range of readers than it would be were it restricted to 
a uniform style of treatment. 


PREFACE TO ORIGINAL EDITION 


The figures illustrating the venation of the wings of insects have been 
drawn with great care under the writer's direction by Mr. E. P. Felt and 
Mr. R. H. Pettit. About one half of those in the chapter on Lepidoptera 
were drawn by Mr. Felt; the others in this chapter and those in the 
chapters on Diptera and Hymenoptera were drawn by Mr. Pettit. 

I wish also to acknowledge the help of my Assistant Mr. A. D. Mac- 
Gillivray, to whom I am indebted for much aid in bibliographical re- 
searches and in many other ways; also, that of Dr. A. C. White of the 
Cornell University Library, who has generously given much time to 
determining the etymologies of many of the more obscure words the pro- 
nunciations of which are indicated in the text. 

To the authorities of Cornell University the authors of this book are 
under deep obligation for aid and encouragement. The preparation of 
the work would not have been possible but for the liberal grants which 
they have made for the purchase of specimens and books. 


John Henry Comstock 


Entomological Laboratory, 

Cornell University, 

December, 1894 


01 


FOREWORD 

The Manual for the Study of Insects, published in 1895, was written 
to meet the needs of teachers of Entomology when that science was in its 
infancy as an academic study. It was well received and accomplished its 
purpose, and there has been a continuous call for it since; it is now in 
its eighteenth edition. Owing to the rapid development of the science it 
became necessary to revise the book and I began this before my retire- 
ment in 19 14. However, so great has been the growth of Entomology 
that this intended revision of the Manual resulted in a new textbook, 
An Introduction to Entomology. 

I still had it in mind to revise the Manual, making it more elemen- 
tary, when failing health prevented. It is with relief and confidence that 
I pass this task on to Professor Glenn W. Herrick, whom I trained when 
he was an undergraduate and who has now many years of successful 
teaching and careful research to his credit. 

John Henry Comstock 

April 5, 1929. 


INTRODUCTION 

Some time during the year 1895, a package containing the 
first volumes of "A Manual for the Study of Insects" fresh from the 
press, came to the Insectary at Cornell University where the writer lived 
and worked as a student in entomology. Professor Mark Vernon Slinger- 
land and the writer rushed with feverish haste to open the box in order 
to see and handle as quickly as possible, this wonderful book, the publi- 
cation of which we had awaited with such great anticipation and interest. 
The event, because of its inspirational value, was almost as significant in 
the life of the writer as it was, for other reasons, in that of the author of 
the book; and now after thirty-odd years it becomes a peculiar pleasure 
to have the opportunity of revising that first Manual of Professor Com- 
stock's. 

The aim of the revision has been to keep the Manual in form and 
arrangement practically as it was first written. The attempt has been 
made, of course, to bring the subject-matter down to date, to simplify it 
and to condense it somewhat in order to bring it within the horizon of 
the beginning student. The more advanced student in entomology has 
been adequately cared for by Professor Comstock's much more extended 
work, "An Introduction to Entomology," and by other works of somewhat 
similar character. 

The writer acknowledges with gratitude, the interest and hearty aid 
of his colleagues, notably that of Dr. O. A. Johannsen who compiled the 
simplified table of the Diptera and who read the manuscript on that 
order; that of Dr. W. T. M. Forbes who formulated the shorter table of 
the Lepidoptera and also read and criticised the text treating of this 
order; that of Dr. J. C. Bradley with the Hymenoptera; and of Dr. 
J. G. Needham from whose' papers and works on the aquatic forms the 
writer has drawn freely. 

Some of the old figures of the Manual have been omitted, notably 
several of those illustrating wing- venation. The need of these is not so 
great at this time for the Comstock-Needham system of naming the 
wing- veins of insects is now thoroughly established and familiar to stu- 
dents and teachers of entomology. Many new figures have been added. 
The writer is indebted to Doubleday, Page and Company for permission 
to use figures 11, 21, 23, 24, 25, 27, 28, 29, and 35, from the "Spider 
Book" by J. H. Comstock, to H. Holt and Company, for figures 270, 
302, and 564, from the "Manual of Injurious Insects," by Glenn W. 
Herrick, to MacMillan Company for figures 13, 30, and 510, from Her- 
rick's "Insects Injurious to the Household" and to Dr. Grace H. Gris- 
wold for figure 598a. 

Glenn W. Herrick 

Ithaca, N.Y. 
Dec. 2, 1929. 


■ • (1 * • 


CONTENTS 

CHAPTER PAGE 

I. Insects and their near relatives: Branch Arthropoda; Class 
Crustacea, Crabs, Lobsters, Crayfish, and others; Class Arach- 
nida, Spiders, Scorpions, Mites, and others; Class Diplop- 

ODA, millipedes; and Class Chilopoda, centipedes I 

II. Class Hexapoda or Insects: characteristics of the class; meta- 
morphoses of insects; external anatomy of insects; internal 
anatomy of insects; table for determining the orders of insects; 

list of the orders of insects 22 

III. Order Thysanura, Bristle-tails, Fish-moths, and others 45 

IV. Order Collembola, Spring-tails 47 

V. Order Orthoptera, Cockroaches, Crickets, Grasshoppers, Locusts, 

and others 49 

VI. Order Zoraptera 62 

VII. Order Isoptera 63 

VIII. Order Neuroptera, the Dobson, Aphis-lions, Ant-lions, and 

others 66 

IX. Order Ephemerida, Mayflies 74 

X. Order Odonata, Dragonflies 77 

XL Order Plecoptera, Stoneflies 81 

XII. Order Corrodentia, Book-lice and others 83 

XIII. Order Mallophaga, Bird-lice 85 

XIV. Order Embiidina 87 

XV. Order Thysanoptera,. Thrips 89 

XVI. Order Anoplura, Sucking Lice 92 

XVII. Order Hemiptera, Bugs 94 

XVIII. Order Homoptera, Plant-lice, Scale-insects and others 109 

XIX. Order Dermaptera, Earwigs 125 

XX. Order Coleoptera, Beetles 127 

XXL Order Strepsiptera, Stylopids 176 

XXII. Order Mecoptera, Scorpion-flies and others 178 

XXIII. Order Trichoptera, Caddice-flies 180 

XXIV. Order Lepidoptera, Moths, Skippers, and Butterflies 183 

XXV. Order Diptera, Flies 286 

XXVI. Order Siphonaptera, Fleas 326 

XXVII. Order Hymenoptera, Bees, Wasps, Ants, and others 329 

Index 385 


12 793 


EXPLANATION OF PLATES 
PLATE I. (Frontispiece) 

FIGURE PAGE 

1. The Carpet Beetle 150 

2. The Twelve-spotted Diabrotica 165 

3. The Adalia bipunctata 153 

4. The Silver-spotted Skipper 260 

5. The American Copper 283 

6. The Red Admiral 270 

7. The Painted Beauty 270 

PLATE II. (Page 34) 
The internal anatomy of a caterpillar. 

PLATE III. (Page 35) 
The internal anatomy of a cockroach. 


CHAPTER I 


INSECTS AND THEIR NEAR RELATIVES 


PHYLUM ARTHROPODA 

The Arthropods 

Zoologists recognize at least twelve great groups or phyla of animals, 
— Protozoa (one-celled animals), Porifera (sponges), Ccelenterata (hy- 
dras, sea-anemones), Platyhelminthes (flatworms), Nemathelminthes 
(roundworms), Trochelminthes (rotifers), Molluscoidea 
(lampshells) , Annulata (earthworms, et al.), Echinoder- 
mata (starfish), Mollusca (clams, oysters), Arthropoda 
(spiders, insects), and Chordata (fishes, birds, mam- 
mals). In organization and development the phylum 
Arthropoda, stands high in the series as indicated in the 
foregoing linear arrangement. Indeed, the arthropods 
stand next to the fishes, reptiles, birds and mammals, 
the highest forms in the animal kingdom. 

If an insect, a spider, a scorpion, a centipede, or a 
lobster be examined, the body will be found to be com- 
posed of a series of more or less similar rings or seg- 
ments joined together; and some of these segments 
will be found to bear segmented legs (Fig. i). All the 
animals possessing these characteristics are classed to- 
gether as the phylum Arthropoda. 

A similar segmented form of the body is found 
among worms; but these are distinguished from the 
arthropods by the absence of legs. It should be re- 
membered that many animals commonly called worms, 
as the tomato-worm, apple-worm, etc., are not true 
worms, but are the larvae of insects (Fig. 2). The earthworm is the 
most familiar example of a true worm. 

In the case of certain arthropods the distinctive characteristics of the 


Fig. 1. — An insect 
showing segmented form 
of body. 


Fig. 2. — Larva of butterfly, Papilio thoas. 


phylum are not evident from a cursory examination. This may be due to 
a very generalized condition; but in most instances it is due to a second- 


THE STUDY OF INSECTS 


Fig. 3. — An Itch-mite: a, from 
below; b, from above. 


ary modification of form, the result of adaptation to special modes of 
life. Thus the segmentation of the body may be obscured, as in spiders 

and in mites (Fig. 3); or the jointed appen- 
dages may be absent, as in the larvae of flies, 
of bees, and of many other insects. In all of 
these cases, however, a careful study of the 
structure of the animal, or of its complete life- 
history, or of other animals that are evidently 
closely allied to it removes any doubt regarding 
its being an arthropod. 

The phylum Arthropoda is the largest of 
the phyla of the animal kingdom, including many more known species 
than all the other phyla taken together. This vast assemblage of ani- 
mals includes forms differing widely in structure, all agreeing, however, 
in the possession of the essential characteristics of the Arthropoda. Several 
distinct types of arthropods are recognized ; and those of each type are 
grouped together as a class. 

The number of distinct classes that should be recognized, and the 
relation of these classes to each other are matters regarding which there 
are still differences of opinion; we must have much more knowledge 
than we now possess before we can speak with any degree of certainty 
regarding them. Some authorities recognize thirteen classes of arthro- 
pods; but since most of them contain forms which are rarely seen by 
most students only the more common representatives will be discussed. 
These are distributed among the following classes: Crustacea, Arachnida, 
Dipjopoda, Chilopoda, and Hexapoda. 


Class CRUSTACEA 


The Crustaceans 

The members of this class are aquatic arthropods, which breathe by true 
gills! They have two pairs of antenna 
and at least five pairs of legs. The 
position of the openings of the reproduc- 
tive organs varies greatly; but as a ride 
they are situated far forward. 

The most familiar examples of the 
Crustacea are the cray-fishes, the 
lobsters, the shrimps, and the crabs. 
Cray-fishes (Fig. 4) abound in our 
brooks, and are often improperly 
called crabs. The lobsters, the 
shrimps, and the true crabs live in 
salt water. 

The Crustacea are distinguished 
from nearly all other arthropods by 
their mode of respiration, being the 
only ones that breathe by true gills. 
Many insects live in water and are 
furnished with gill-like organs; but 
these are either tracheal gills or blood- 


FlG. 4. — A Cray-fish. 


INSECTS AND THEIR NEAR RELATIVES 3 

gills, organs which differ essentially in structure from true gills, as de- 
scribed later. The Crustacea also differ from other Arthropoda in having 
two pairs of antennae. Rudiments of two pairs of antennae have been 
observed in the embryos of many other arthropods; but in these cases 
one or the other of the two pairs of antennae fails to develop. 

The examples of crustaceans named above are the more conspicuous 
members of the class; but many other smaller 
forms abound both in the sea and in fresh water. 
Some of the more minute fresh-water forms are 
almost sure to occur in any fresh-water aquarium. 

In Figure (5) are represented three 

of these enlarged. The minute 

crustaceans form an important b, Y Cydop7i?, T Daphn?a. a,Cypris; 

element in the food of fishes. 

Some crustaceans live in damp places on land, and are 

often found by collectors of insects; those most often ob- 
Fig. 6. — a Sow- served are the sow-bugs (Oniscoida), which frequently 
bug " occur about water-soaked wood. ~ Figure (6) repre- 

sents one of these. 

Class ARACHNIDA 
Scorpions, Harvestmen, Spiders, Mites, and others 

The members of this class are air-breathing arthropods , in which the 
head and thorax are usually grown together, forming a cephalothorax, which 
has four pairs of legs, and which apparently has no antennas. The reproduc- 
tive organs open near the base of the abdomen. 

The Arachnida abound wherever insects occur, and are often mistaken 
for insects. But they can be easily distinguished by the characters given 
above, even in those cases where an exception occurs to some one of 
them. The more important of the exceptions are the following: in one 
order, the Solpugida, the head is distinct from the thorax; as a rule the 
young of mites have only six legs, but a fourth pair is added during 
growth; and in the gall-mites there are only four legs. 

The Arachnida arc air-breathing; but it is believed that they have 
been evolved from aquatic progenitors. Two forms of respiratory organs 
exist in this class: first, book-lungs; and second, tubular tracheae. Some 
members of it possess only one of these types; but the greater number 
of spiders possess both. 

The Arachnida lack true jaws. Therefore they do not masticate their 
prey and swallow the parts. They crush their victims and suck out the 
juices. The first pair of organs on the cephalothorax constitutes the 
principal crushing organs. They are modified antennae and are known as 
chelicerae. Other appendages, however, may aid in the crushing process. 
Each one of the second pair of appendages just behind the chelicerae 
is leglike in form. These are known as the pedipalps. Following the 
pedipalps are the four pairs of legs. Thus the cephalothorax of the 
Arachnida bears six pairs of appendages. The Arachnida have only 
simple eyes. 

The more familiar forms of this class are the scorpions, harvestmen, 
spiders, and mites. 


4 THE STUDY OF INSECTS 

Order PEDIPALPIDA 

The II 7/ ip -scorpions 

These strange creatures are found in our country only in the extreme 
southern part for they are tropical animals; but they are distributed 
from the Atlantic to the Pacific. In their general form they bear some 

resemblance to the scorpions; but 
they can be easily distinguished from 
the scorpions by the form of the first 
pair of legs and of the post-abdomen. 
The front legs are greatly elongated 
(Fig. 7) and have the tarsi broken 
up into many small slender segments 
giving this part of the leg a whip-lash- 
like appearance. In addition, the 
members of one family have the 
caudal end of the abdomen furnished 
with a slender, many-segmented ap- 
pendage resembling a tail. These 
forms are known as the " tailed whip- 
scorpions" (Fig. 7). There is, how- 
ever, but one species of this family 
in the United States, the giant tailed 
whip-scorpion, Mastigoproctus gigan- 
teus, which, when full-grown, attains 
a length of from four to five inches 
(Fig. 7). Its bite is said to be poison- 
ous but direct, authentic evidence of 
its supposed venomous quality is lack- 
ing. This species burrows in sand 
under logs or other objects lying on the ground ; it doubtless feeds on any 
insects that it can capture. 

There is another family of these creatures known as the tailless whip- 
scorpions because the individuals lack the tail-like appendage of the ab- 
domen so conspicuous in the tailed species. The front legs, however, of 
these tailless forms are even more whip-lash-like in appearance than those 
of the giant whip-scorpion but the body is relatively shorter and broader. 
There are only four species of this family found in this country and these 
are in the extreme South. They are smaller than the giant whip- 
scorpion. 

There is a third family represented by a single species in the United 
States Trithyreus pentapeltis, which is less than one-half an inch in length. 
It lives in the desert regions of Southern California. 


Fig. 7. — Mastigoproctus giganteus. 


Order SCORPIONIDA 

The Scorpions 

The scorpions (Fig. 8), have the body divided into a compact, un- 
segmcntcd cephalothorax, and a long, segmented abdomen. The ab- 
domen is divided into two portions: a broad pre-abdomen, consisting of 


INSECTS AND THEIR NEAR RELATIVES 


seven segments; and a slenderer tail -like division, the post-abdomen, 
consisting of five segments. At the end of the post-abdomen there is a 
large poison-sting, which appears like a segment. 
The chelicerae and the pedipalpi are provided with 
pincers. The pedipalpi resemble in a striking man- 
ner the great claws of lobsters. The cephalothorax 
bears from three to six pairs of eyes. Scorpions 
breathe by means of lung sacs, of which there are 
four pairs, opening on the lower side of the third 
to the sixth abdominal segments. 

Full-grown scorpions possess a pair of comb-like 
organs on the lower side of the second abdominal 
segment. The function of these organs may be 
tactile. 

The sexes of scorpions differ in that the male has 
broader pincers and a longer post-abdomen. Scor- 
pions do not lay eggs, the young being developed 
within the mother. After the birth of the young, 
the mother apparently shows great regard for them, 
carrying them about with her for some time, at- 
tached by their pincers to all portions of her body. 

Scorpions live in warm countries. They are com- 
mon in the southern portion of the United States, 
but are not found in the North. They are nocturnal, remaining concealed 
during the day, but leaving their hiding-places at dusk. When they run 
the post-abdomen of some species is bent upwards over the back. They 
feed upon spiders and large insects, which they seize with the large pin- 
cers of their palpi, and sting to death with their caudal poison sting. 

The sting of a scorpion rarely if ever proves fatal to a grown man, 
although the larger species, which occur in the Tropics, produce serious 
effects by their stings. 


Fig. 8. — A Scorpion. 


Order PSEUDOSCORPIONIDA 

The Pseudoscorpions 

The pseudoscorpions are small arachnids which resemble scorpions in 
the form of their pedipalps and of their body, except that the hind part 
of the abdomen is not narrow, as is the post-abdomen of scorpions, 
and they have no caudal sting. The abdomen is broad, 
flat, and thin and only one or two pairs of eyes are present 
on the cephalothorax. 

The pedipalps are enormously developed and are chelate, 
resembling those of the scorpions (Fig. 9). The pseudoscorp- 
ions are especially interesting because they possess silk glands 
in the cephalothorax which open near the tip end of each 
chelicera. The silk which they spin is used for making a 
fig. 0. — a Pseu- web or cocoon in which the pseudoscorpion can retreat dur- 
ing the moulting period and during the winter. 
There are many species of pseudoscorpions in the United States, found 
in the North as well as in the South. They live under stones, beneath 
the bark of trees, in moss, under leaves on the ground, in the nests of 


6 THE STUDY OF INSECTS 

bees, of ants, and of termites and in households where they are often 
found between the leaves of books. It is believed that they live on mites 
and minute insects. They are often found attached to flies and beetles 
and according to one observer they sometimes kill the flies and eat them. 

Order PHALANGIDA 
The Harvestmen, or Daddy-long-legs 

The harvestmen are very common in most parts of the United States. 
They are well known to children in this country under the name daddy- 
long-legs, but as this name is also sometimes applied to crane-flies, har- 
vestmen is preferable. In some sections of the country the harvestmen 
are known as grandfather graybeards. 

Most harvestmen can be recognized by their very long and slender 


Fig. io — The Striped Harvestman 


legs (Fig. io) although some species have comparatively short ones. The 
cephalothorax is indistinctly if at all segmented. The abdomen is short, 
broad, consists of nine segments, and is without a tail-like appendage; it 
is broadly joined to the cephalothorax. 

The eyes of the harvestmen are two in number, and are situated on a 
prominent tubercle near the middle of the cephalothorax. The chelicerae 
are pincer-like. Their pedipalpi are four-jointed, and are small compared 
with the pedipalpi of the preceding orders; they resemble in form the 
palpi of insects. The members of this order breathe by tracheae, which 
open by a single pair of spiracles, on the lower side of the body at the 
junction of the cephalothorax and abdomen. 

There seems to be some uncertainty regarding the food of harvestmen. 
Some writers say they live on dead insects while others aver that they 
feed on live aphids and other small insects. It seems clear that they 
also suck the juices of fruits and soft vegetables. 

In the North most harvestmen die in the autumn after they have 
deposited eggs under stones, or in crevices or in the ground. These eggs 
do not hatch until the following spring. In the South more of the adults 
hibernate under rubbish during the winter. 

No silk glands have been found in the harvestmen and they do not 
make webs like the spiders. 

Order ARANEIDA 

The Spiders 

The spiders differ from other Arachnida in having the abdomen un- 
segmented and joined to the cephalothorax by a short, narrow stalk. 


INSECTS AND THEIR NEAR RELATIVES 


The cephalothorax is also unsegmented ; and the abdomen bears at its 
end organs for spinning silk (Fig. n). 

The cheliceras (Fig. 12, md) consist of two segments, a strong basal 
one and a claw-shaped terminal 
one, at the tip of which a poison 
gland opens (Fig. 13). It is by 
means of these organs that spiders 
kill their prey. The pedipalpi are 
leg-like in form, but differ greatly 
according to sex. In the female 
the last segment of the pedipal- 
pus resembles a foot of the spider, 
and is usually armed with a well- 
developed curved claw. But in 
the male the corresponding seg- 
ment is more or less enlarged, and 
very complicated in structure 
(Fig. 14). The greater number of 
spiders have four pairs of eyes, but 
there may be only one, two, or 
three pairs; and certain cave 
spiders are blind. Spiders breathe by means of lung-sacs, of which there are 
one or two pairs ; and some have tracheae also. The lung-sacs open on the 


Fig. 11. — The banana spider showing division of body 
into cephalothorax and abdomen. 


Fig. 12. — Lower side 
of cephalothorax of a 
spider; md, chelicera; 
mx, maxilla; p, paipus; 
/, lower iip; s, sternum. 


Fig. 13. — Chelicera of a spider: p, 
poison gland; d, duct; o, opening at 
tip of fang; /, fang. 


Fig. 14. — Maxilla 
and palpus of male 
house-spider. 


Fig. 15. — End of abdomen 
of spider, showing six spinn-r- 
ets spread apart; in front of 


lower side of the abdomen near its base, 
and between them is the opening of the 
reproductive organs . The tracheae open 
through a single spiracle near the hind 
end of the body, usually just in front 
of the spinning organs. 

The spinning organs, which are sit- FlG l6 _ A Rroup 
these'^Thesp^cie.'and'behind uated near the end of the abdomen, of spinning tubes, 
them the opening of the aiimen- CO nsist of one or two or three pairs of gI 

tary canal. . l , . . 

spinnerets. These appendages (tig. 15) are more or 
less finger-like in form, and sometimes jointed. Upon the end of each spin- 
neret there are many small tubes, the spinning tubes, from which the silk is 
spun (Fig. 16). Some spiders have one hundred or more of these spinning- 


8 THE STUDY OF INSECTS 

tubes on each spinneret. The silk is in a fluid state while it is within 
the body, but it hardens as soon as it comes in contact with the air. 

Ordinarily the tips of the spinnerets are brought close together, so that 
all the minute threads that emerge from the numerous spinning tubes 
mite to form a single thread. This, however, may be so delicate as to be 
invisible, except in a favorable light. Sometimes a spider will spread its 
spinnerets apart, and thus spin a broad ribbon-like band. We have 
observed a spider seize a large grasshopper which was entangled in its 
web, and, rolling it over two or three times, completely envelop it in a 
sheet of silk spun from its spread-apart spinnerets. 

In the construction of their webs the orb- weaving spiders make use of 
two kinds of silk. One of these is dry and inelastic ; the other, viscid and 
elastic. This fact can be easily seen by examining an orb web. If the 
spiral line which forms the greater part of the web be touched, it will ad- 
here to the finger, and will stretch, when the finger is withdrawn, to several 
times the original length. But if one of the radiating lines or a portion of 
the outer framework be touched, it will neither adhere to the finger nor be 
stretched. If the spiral line be examined with a lens, it will be found to 
bear numerous bead-like masses of viscid matter (Fig. 17); 

~H-~ ~\^ this explains its adhesiveness. 

^-4 — - — — V"~ It is supposed that the two kinds of silk are spun from 

—J. \^ different spinnerets. When this silk is first spun the viscid 

matter forms a continuous layer of liquid on the outside of 

fig. 17.— viscid silk ft g u t verv soon this layer breaks up into 

from an orb web. , , ,-, • • -i 

the bead-like masses — ma way similar to \ 
that in which the moisture on a clothes-line on a foggy day 
collects into drops. 

Spiders of the two families Dictynidos and Uloboridce have FlG ™'"_ End of 
spinning organs differing from those of all other spiders, a b jj°™ e J? showin s cri - 
Thcy have in front of the usual spinnerets an additional 
organ, which is named the cribellum (Fig. 18). This bears spinning-tubes 
like the other spinnerets, but these tubes are much finer. These spiders 
C have also on the metatarsus of 

-^g^-^^^S^^^^^^^^#^ thc hind le S s one or . two TOW . s 
^^^^^^^^^^^^m^ of curved spines: this organ is 

^^^^^^^^^^^^^^^^^^^ the calamistrum (Fig. 19). By 

means of the calamistrum 

Fig. 19. — Metatarsus of hind leg of spider showing calamistrum, c. ,i SoiderS COmb from the 

cribellum a band of loose threads, which forms a part of their webs. 

Spiders make use of silk in the construction of their webs or snares, in 
the building of tubes or tents within which they live, in the formation of 
egg-sacs, and in locomotion. 

Figure 20 represents the large egg-sac of one of the orb weavers. This 
is made in the autumn, and contains at that season a large number of 
eggs — five hundred or more. These eggs hatch early in the winter; 
but no spiders emerge from the egg-sac until the following spring. If 
egg-sacs of this kind be opened at different times during thc winter, the 
spiders will be found to increase in size but diminish in _ number as the 
season advances. In fact, a strange tragedy goes on within these egg- 
sacs: thc stronger spiders calmly devour their weaker brothers, and in 
the spring those which survive emerge sufficiently nourished to fight their 
battles in the outside world. 


INSECTS AND THEIR NEAR RELATIVES 


The egg-sacs of the different species of spiders vary greatly in form. 
In some, as in that figured below, the outer covering is very dense, while 


Fig. 20. — Egg-sac of Argiope. 


Fig. 21. — Lycosa with thin egg-sac. 


in others the outer part consists of thin flossy silk (Fig. 21). One of the 
most common kinds is very flat, silvery in color, and is firmly attached 
to stones lying upon the ground (Fig. 22). 

Every one knows that a spider wishing to descend 
to some place beneath it simply fastens a line to the 
object which it is upon and then drops boldly off, regu- 
lating the rate of its descent by spinning the line 
rapidly or slowly; when the spider wishes to return, it 
has only to climb up the same line. 

Frequently spiders pass from point to point in a F IG - . ? 3 - — E es sac on 

, . 7 1 i- . • 1 r "11 i • 1 rr-M under side of a stone. 

horizontal direction by means of silken bridges. I hese 
are formed in this way: the spider spins out a thread, which is carried off 
by a current in the air. After a time the thread strikes some object and 
adheres to it; then the spider pulls the line tight, and fastens it where it 
is standing. It then has a bridge, along which it can easily run. 

But more remarkable than either of these uses of silk for locomotion is 
the fact that many spiders are able to travel long distances, hundreds of 
miles, through the air by means of these silken threads — 

"sailing mid the golden air 
In skiffs of yielding gossamere." — (Hogg.) 

The aeronautic spiders, or flying spiders, as they are more commonly 
called, are frequently very abundant, especially on warm autumn days. 
At such times innumerable threads can be seen streaming from fences, 
from bushes, and the tips of stalks of grass, or floating through the air. 
The flying spider climbs to some elevated point, which may be merely 
the tip of a stalk of grass, and then, standing on the tips of its feet, lifts 
its body as high as it can, and spins out a thread of silk. This thread is 
carried up and away by a current of air. When the thread is long enough 
the force of the air current on it is sufficient to buoy the spider up. It 
then lets go its hold with its feet and sails away. These spiders travel 
long distances over the sea far from land in this manner. 


IO 


THE STUDY OF INSECTS 


Representatives of thirty families of spielers are found in the United 
States but only a few common forms can be discussed here, those which 
best illustrate the habits of these most interesting animals. The spiders 
will, however, well repay one for further study of them. With the excep- 
tion of the hour-glass spider, common in the South and the tarantulas 
found in the Southwest, spiders are harmless creatures and as safe to 
observe and handle as beetles or ants. 


Family AViculariid^; 
The Tarantulas and the Trap-door Spiders 

Those who live in the warmer parts of our country know well the 
large spiders commonly called tarantulas. These are the giants among 
spiders, some of them being the largest known; but some species of this 
family are not very large. They arc dark-colored, hairy spiders, and can 
be distinguished from the other families mentioned here by the fact that 
the cheliceree work up and down instead of sidewise. 

The members of this family have various habits. Some live in the 
cracks of trees or under stones or rubbish on the ground or sometimes 
in a simple cell dug in the earth and lined with a slight web of silk. 
Others dig definite tunnels in the ground, line them with silk and in 
many cases close the opening with a door or lid. Others spin webs 
resembling those of the grass-spiders known as the funnel-web weavers. 

One of the best 
known of the tarantulas 
is Eurypehna hentzi. This 
species occurs in the 
southern and southwest- 
ern states, and is one of 
the largest of our spiders 
(Fig. 23). Several 
closely allied species are 

Fig. 23. - A Tarantula, Eurypdma hentzi. found in California. 

But the members of this family that have attracted most attention 
on account of their habits are the trap-door spiders. These dig a tube 
in the ground, as do many other members of this family; but thi s tube is 
lined with a denser layer of silk, and is provided 
with a hinged lid, which fits the opening of the 
tube with wonderful accuracy (Fig. 24). The 
spider hides in this nest when not seeking its 
prey. Some species take the precaution to build 
a branch to their nest, and to provide this 
branch with a door. As this door forms a part 
of one side of the main tube, it is not likely to 
be observed by any creature which may find 
its way past the first door of the nest. 

Several species of trap-door spiders occur in 
the southern and southwestern states. The hab- 
its of many of these spiders are not yet known. 
They should be studied much more. 


Fir.. 24. — Entrance to tunnel of 
trap-dooT spider. (From the Spider 
Book, Doubleday, Page and Co.) 


INSECTS AND THEIR NEAR RELATIVES 


ii 


Family Agelenid^e 
The Funnel-web Spiders 

Even the most careful observers seldom realize what an immense 
number of spider-webs are spun upon the grass in the fields. But oc- 
casionally these webs are made visible in the early morning by the dew 
which has condensed upon them. At such times we may see the grass 
covered by an almost continuous carpet of silk. 

The greater number of the webs seen at such times are of the form 
which we term funnel-webs. They consist of a concave sheet of silk, 
usually with a funnel-shaped tube at one side, and numerous lines extend- 


Fig. 25. — Web of Agelena. 

ing in all directions to the supporting spears of grass (Fig. 25). The 
tube serves as a hiding-place for the owner of the web; from this retreat 
the spider runs out on the upper surface of the web to seize any insect 
that alights upon it. The tube opens below, near the roots of the grass; 
so that the spider can escape from the web if a too formidable insect 
comes upon it. 

The funnel-web spiders are long-legged usually brownish individuals 
with the hind pair of spinnerets very long while the feet have three 
claws. The eyes of these spiders are eight in number and arranged in 
two rows. 

Probably the most common spider in our fauna is the grass-spider or 
funnel-web weaver (Agelena noma) whose webs are found everywhere 
during the summer spun on the grass. The webs are most conspicuous 
in the early morning when the dew has condensed on them. 

To this family also belongs the remarkable aquatic spider of Europe 
(Argyroneta aquatica) which lives among plants at the bottom of clear 
quiet ponds. It breathes air adhering to its body which it brings from 
above the surface of the water. 

Family Dictynid^e 

The Hackled-band Spiders with irregular webs 

Certain spiders are remarkable for using two kinds of silk in the for- 
mation of their webs. Thus, as explained later, the orbweavers build 


12 


THE STUDY OF INSECTS 


Fig. 26. — 
Curled thread of 
a Dictynid, en- 
larged. 


the framework of their orbs of dry and inelastic threads, and attach to 
this framework a thread which is sticky and elastic; while most spiders 
which make irregular webs use only one kind of silk. There are, how- 
ever, certain species of irregular web-weavers which use two kinds of 
silk. One of them is a plain thread like that spun by other spiders, and 
the other is a peculiar ribbon-like thread or band with curled threads 
running through it. This ribbon-like band with its curled threads we 
have called the hackled-band. 

The hackled-band weavers represent 
two families, one of which makes irregu- 
lar webs; the other, those which are of 
definite form. The first of these is the 
Dictynidag. 

The hackled-band is made in the same 
way by both families. It is composed of 
silk spun probably partly from certain of 
the spinnerets and partly 
from the cribellum (page 8); 
and is combed into its pecul- 
iar form by means of the 
comb of stiff hairs, the cala- 
mistrum, which is borne by 
the metatarsus of the hind 
legs (see page 8). In mak- 
ing the hackled-band the spider turns one 
of its hind legs under the abdomen so 
that the calamistrum is just under the 
spinnerets and makes a rapid combing 
motion. By the rapid combing motions 
of the hind legs the calamistrum finally 
combs out from the spinning-tubes a 
flat-thread and at the same time tangles 
through it some curled threads; but it is 
difficult to determine just how the 
hackled-bands are given their charac- 
teristic form and the whole process is 
not well understood. 

This band of tangled or curled threads 
is easily seen in the webs of these spiders, 
being wider than the ordinary threads 
and white in color. In old webs it becomes conspicuous by the large amount 
of dust which it collects. Figure 26 shows the appearance of this band when 
magnified, and the way in which it is attached to the plain threads. 

Our more common dictynids make webs of various shapes, on fences, 
under stones, in holes in rotten logs, and on plants. These webs are 
especially common among the flowers of golden-rod and other plants 
having clusters of small flowers (Fig. 27), and exhibit a slight degree of 
regularity. 


Fig. 27. — Web of dictynid. 


INSECTS AND THEIR NEAR RELATIVES 


13 


Family Uloborid^ 
The Hackled-band Spiders with regular webs 

We have already described the ribbon-like threads, or hackled-bands 
of the dictynids (p. 12), and the curious organs called cribellum and 
calamistrum, by which these curled threads are made (p. 8). Similar 
organs and a similar habit are possessed by the spiders of the family 
Uloboridae. These spiders, however, make webs which are regular in form. 
There are only two genera belonging to this family in the United States; 
but as the webs made by these are very different, we will describe both. 

The triangle spider, Hyptiotes cavatus. — This spider is common all 
over New England and the Middle States, and has been found as far to 
the Southwest as Texas. Its web is most often found stretched between 


Web of triangle spider. 


the twigs of a dead branch of pine or spruce. At first sight this web 
appears like a fragment of an orb web (Fig. 28); but a little study will 
show that it is complete. The accompanying figure, from a photograph 
of a web of the triangle spider spun between two dead twigs of a pine 
tree, illustrates the form of the web. It consists of four plain lines 
corresponding to the radiating lines of an orb web, and a series of double 
cross lines, which are spun by the cribellum and calamistrum. From the 
point where the radiating lines meet a strong line extends to one of the 
supporting twigs. Near this twig the spider rests, pulling the web tight 
so that there is some loose line between its legs, as shown in the enlarged 
figure. When an insect becomes entangled in one of the cross lines, the 
spider suddenly lets go the loose line so that the whole web springs for- 
ward, and the insect is entangled in other cross threads. The spider then 
draws the web tight and snaps it again. This may be repeated several 
times before the spider goes out upon the web after its prey. 


14 


THE STUDY OF INSECTS 


Uloborus. — The spiders of this genus make round webs which re- 
semble at first sight those of the orb weavers; but they differ from the 
ordinary orb webs in that the spiral thread is made of the hackled-band 
silk. These webs are nearly horizontal, and are usually made between 
stones or in low bushes. The spiders of this genus are not common, but 
they are widely distributed. 


Family Theridiidve 

The Comb-footed Weavers 

Many are the kinds of webs spun by different spiders. Some of them, 
as the orb webs and the funnel-webs, delight us with their wonderful 
regularity of form; while others appear to be a mere shapeless maze of 
threads. Such are the structures whose presence in the corners of our 
rooms torment thrifty housewives, and which arc disrespectfully termed 
cobwebs. The most common spinner of cobwebs is the abundant house- 
spider, Theridion tepidariorum, which spins its irregular webs composed 
of threads extending in all directions with no apparent regularity, in any 
convenient corner. The spider, which hangs in its web with its back 
downwards, will serve well as a representative of this family. 

These spiders have eight eyes and 
three tarsal claws. In addition, they 
have on the tarsus of the fourth pair 
of legs a distinct comb consisting of a 
row of strong, curved, and toothed 
setae (Fig. 29). As the presence of this 
tarsal comb distinguishes these spiders 
from all others, they may well be called 
the comb-footed spiders. The comb is 
used for flinging silk, often in a quite 
liquid state, over the entangled prey. 
Although the house-spiders are the most famil- 
iar members of this family, a large number of 
species spin their webs in the fields on bushes. 
These webs usually consist of a flat or curved 
sheet, under which the spider hangs back 
downward. This sheet is supported by threads 
running in all directions to the neighboring ob- 
jects. Frequently there is a large number of 
these supporting threads above the web, which 
serve the additional purpose of impeding the 
flight of insects, and causing them to fall into 
the web, where they are caught. A few species 
which do not live in webs and spin very little, 
are found under stones, or in the moss and 
leaves, and run with great rapidity. 

One spider of this family, Latrodcctits mac- 
lans, commonly known as the "black widow" 
or hour-glass spider is, outside of the tarantulas, the one poisonous spider 
in this country. It is a coal-black spider with a red marking in the form of 
an hour-glass on the underside of the abdomen (Fig. 30). The female is 


Fir,. 2Q. — Comb of Theridion; b, a tooth 
of comb, enlarged. (From the Spider Book, 
Doubleday, Page and Company.) 


Fig. ?o. — The hour glass spider. 
Ventral side aboye to show the red 

marking 


INSECTS AND THEIR NEAR RELATIVES 


15 


about one-half an inch in length. This spider is common all over the 
southern states and occurs as far north as Pennsylvania and Ohio, at least. 

Family Argiopid^e 
The Orb Weavers 

Few if any of the structures built by lower animals are more wonder- 
ful than the webs of orb-weaving spiders, but these beautiful objects are 
so common that they are often considered hardly worthy of notice. If 
they occurred only in some remote corner of the earth, every one would 
read of them with interest. 

The webs of the different species of orb weavers differ in the details of 
their structure, but the general plan is quite similar. There is first a 
framework of supporting lines. The outer part of this framework is 
irregular, depending upon the position 
of the objects to which the web is 
attached; but the more central part 
is very regular, and consists of a num- 
ber of lines radiating from the center 
of the web (Fig. 31). All of these sup- 
porting lines are dry and inelastic. 
But there is spun upon the radiating 
lines in a very regular manner a thread 
which is sticky and elastic (Fig. 17, 
p. 8). Usually this sticky thread is 
fastened to the radiating lines so as to 
form a spiral, but a few species make 
webs in which this thread is looped 
back and forth. 

Many of the orb weavers 
strengthen their webs by spinning a 
zigzag ribbon across the center. This 
ribbon is made by spreading the 
spinnerets apart so that the minute 
threads from the spinning-tubes do not unite to make a single thread, as 
is usually the case. 

Some of the orb weavers live in their webs hanging head downward, 
usually near the center of the web; others have a retreat near one edge 
of the web, in which they wait for their prey. While resting in these 
retreats they keep hold of some of the lines leading from the web, so 
that they can instantly detect any jar caused by an entrapped insect. 

When an insect in its flight touches one of the turns of the sticky 
line, the line sticks to it; but it stretches so as to allow the insect to 
become entangled in other turns of the line. If it were not for this elas- 
ticity of the sticky line, most insects could readily tear themselves away 
before the spider had time to reach them. 

In making its web an orb weaver first spins a number of lines extend- 
ing irregularly in various directions about the place where its orb is to be. 
This is the outer supporting framework. Often the first line spun is a 
bridge between two quite distant points. This is done as described on 
p. 9. Having a bridge across the place where the web is to be, it is an 


Fig. 31. — Partially completed web of Argiope. 


j 6 THE STUDY OF INSECTS 

easy matter for the spider to stretch its other lines where it wishes them. 
In doing this it fastens a thread to one point, and then walks along to 
some other point, spinning the thread as it goes, and holding it clear of 
the object on which it is walking by means of one of its hind legs. When 
the second point is reached the thread is pulled tight and fastened in 

place. 

After making the outer framework the radiating lines are formed. A 
line is stretched across the space so as to pass through the point which is 
to be the center of the orb. In doing this the spider may start on one 
side, and be forced to walk in a very roundabout way on the outer frame- 
work to the opposite side. It carefully holds the new line up behind it as 
it goes along, so that it shall not become entangled with the lines on 
which it walks; one or both hind feet serve as hands in these spinning 
operations. The spider then goes to the point where the centre of the orb 
is to be, and fastening another line there, it walks back to the outer 
framework, and attaches this line an inch or two from the first. In this 
way all of the radiating lines are drawn. The next step is to stay these 
radii by a spiral line which is begun at the center, and attached to each 
radius as it crosses it. The turns of this spiral are as far apart as the 
spider can conveniently reach, except at the center of the w r eb. All of the 
threads spun up to this stage in the construction of the web are dry and 
inelastic. The spider now proceeds to stretch upon this framework a 
sticky and elastic line, which is the most important part of the web, the 
other lines being merely a framework to support it. In spinning the 
sticky line the spider begins at the outer edge of the orb, and passing 
around it fastens this line- to each radius as it goes. Thus a second spiral 
is made. The turns of this spiral arc placed quite close together, and the 
first spiral, which is merely a temporary support, is destroyed as the 
second spiral progresses. Figure 3 1 represents a web in which the second 
spiral is made over the outer half of the radii. In this figure, aa repre- 
sents the temporary stay-line; 66 the sticky spiral; and cc the fragments 
of the first spiral hanging from the radii. 

The orb weavers arc 1 three-clawed, eight-eyed, sedentary spiders. The 
tarsi are more or less clothed with hairs; but they lack the comb charac- 
teristic of the Theridiidae. They are fairly common, many of our large 
garden spiders being common representatives. 

Family Thomisid^; 
The Crab Spiders 

There arc certain spiders which are called crab spiders, on account of 
the short and broad form of the body, and the curious fact that they 
can walk more readily sidewise or backward than forward. 

These spiders spin no webs, but lie in wait for their prey. They live 
chiefly on plants and fences, and in the winter hide in cracks and under 
stones and bark. Most of the species are marked with gray and brown, 
like the bark upon which they live. Some species conceal themselves in 
flowers, where they lie in wait for their prey. These are brightly colored, 
like the flowers they inhabit; so that insects visiting flowers may alight 
within reach of a spider before seeing it. 

In this family the legs arc turned outward and forward more than 


INSECTS AND THEIR NEAR RELATIVES 


17 


Fig. 32. — Misumena valia. 


downward; so that the body is carried close to the ground. The legs of 
the second pair are as long as or longer than those of the fourth pair. 
The eyes are small, nearly equal in size, and arranged in two rows. 

One of the best-known members of 
this family is the female of Misumena 
vdtia, which is frequently found in 
flowers (Fig. 32). She is remarkable 
for the change in the color of her body 
which takes place when she migrates 
from one flower to another of different 
color. In the spring the female frequents 
the white flowers of trillium, fleabanc, 
and other plants. She then has a ground 
color of white. Later in the season when 
she migrates to golden-rod or other yel- 
low flower her body becomes yellow in 
color. 

Family Lycosid^ 

The Running Spiders 

Every collector of insects who has searched for specimens under stones 
and logs is familiar with the large, dark-colored, hairy spiders often 
found in these places. These spiders frequently attract especial attention 

by dragging after them a 

large _ gray ball (Fig. 33); 

this is the egg-sac, which 

the female carries about 

with her attached to her 

spinnerets. These spiders 

run swiftly; and as they 

depend on the use of their 

legs for the capture of their prey, they are well termed running spiders. 

These spiders resemble in general appearance and in habits the 

tarantulas of the South and the West. But none of our species attain 

the great size of some of the tarantulas, and in the running spiders the 

claw of the chelicerae moves horizontally 
instead of vertically. 

In this family the body is hairy and 
usually much longer than broad. The eyes 
differ markedly in size, and are arranged in 
three rows. The larger eyes arc not in the 
front row. The legs are rather long and 
quite stout. 

Like the tarantulas, some of the running 
spiders build tubular nests in the ground, 
which they line with silk. Sometimes the 
entrance to these nests is concealed by small 
sticks and leaves, and sometimes the spider 
builds a regular turret over the entrance of 
■ its tube (Fig. 34). These nests are used 
mostly as retreats. A few species spin webs. 


Fig. 33. — Lycosa and egg-sac. 


Fig. 34. — Fntrnnce t 
spider, Lycosa. (After Marx.) 


1 8 THE STUDY OF INSECTS 

The larger members of our common species belong to the genus 
Lycosa. These drag after them their egg-sacs as described above; and 
when the young hatch they climb on their mother's back, and are carried 
about for a time. Whether the mother provides nourishment or not for 
the young during this period has not been definitely determined. 


Family Attid^e 
The Jumping Spiders 

The jumping spiders are of medium size, with a short body and short 

stout legs (Fig. 35). They are common on 
plants, logs, fences, and the sides of buildings. 
They are very apt to attract attention by 
their peculiar appearance; their short stout 
legs, bright colors, conspicuous eyes, and 
quick, jumping movements being very differ- 
ent from those of ordinary spiders. 

The eyes are arranged in three rows; 
those of the front middle pair are the largest, 
and are very conspicuous. These self-pos- 
sessed spiders are able to stare an ordinary 
observer out of countenance. They move 
sidewise or backward with great ease, and can 
jump a long distance. They make no webs 
except nests in which they hide in winter or 
when moulting or laying eggs. They are 
hunters, pursuing their prey or springing upon 
it when it comes near them. 

In certain members of this family the 
body is longer than in the typical forms, and 


. — A jumping spider, Salti- 
(From the Spider Book, 
Doubleday, Page and Company.) 


ant-like in appearance. 


Order ACARINA 
The Mites 


In this order the abdomen is unsegmented and broadly and closely 
joined with the thorax usually giving the entire body a more or less sac- 
like appearance. In many members of this order the body is divided into 
two regions which resemble the cephalothorax and abdomen of other 
arachnids but really the regions are not the same in their structure and 
make up. In many mites the body is marked by numerous transverse, 
fine lines, which are so impressed as to appear like the divisions between 
minute segments (Fig. 38). 

As a rule the cheliceras are of characteristic form and often chelate but 
in many of the mites and ticks they are modified into slender, nccdle-like 
organs, fitted for piercing and sucking. 

As in most arachnids the normal number of legs is eight but almost 
always the newly-hatched young have only six legs (3 pairs) while the 
adult members of the gall-mites, family Eriophyidce, have but two pairs 
of legs. With the exception of a few species the mites reproduce by 
laying eggs. 


INSECTS AND THEIR NEAR RELATIVES 


19 


The majority of mites are very small but a few, especially the ticks, 
are of considerable size. The mode of life of the different members of 
this order varies greatly; some are parasitic upon animals; others infest 
living plants; and many feed upon dead animal or vegetable matter, 
thus acting as scavengers. 

Among the mites that are parasitic upon animals are the various ticks, 


Fig. 36. — The southern 
cattle-tick, Bnophilus annulaius. 


Fig. 37. — An Itch-mite: 
below; b, from above. 


a, from 


which are very common in the warmer parts of our country. The com- 
mon cattle-tick (Fig. 36) of the southern states is a very injurious parasite 
of cattle because it not only sucks the blood of its host but it carries from 
one animal to another the organism which causes a serious fever among 
the cattle known commonly as Texas-fever but more properly splenic 
fever. 

The itch-mite is a well-known parasite, infesting man and causing 
the disease known as itch. The sensation characteristic of this disease 
is due to the burrowing of the mites in the skin; and the efficiency of 
sulphur ointment in checking this disease is due to the fact that by the 
use of it the mites are killed. Figure 37 represents an itch-mite greatly 
enlarged. 

Parasitic mites are frequently found attached to insects; a common 
species occurs beneath the wings of locusts. 

The best known of the mites that infest plants is the one commonly 
called the red spider. This lives upon house-plants; and in the warmer 
parts of the country, it infests fruit-trees, cotton, and other plants in 
the open air. On house-plants and in the greenhouse it can be subdued 
by a liberal use of water. 

Some of the mites that infest 
plants produce galls. These galls are ^x J*s?£$firi 

of various forms, but differ from those 
produced by gall-flies (Family Cynip- 
idce of the Order Hymenoptera) in 
having open mouths, from which the 
young mites escape. 

A common disease of the pear, 
caused by the pear-leaf blister-mite, 
is produced by a four-legged mite Phyllocoptes pyrl, (Fig. 38). The blisters 
characteristic of the disease are swellings of the leaf, within which there 


Fig. 38. — Phyllocoptes pyri, greatly enlarged. 


20 


THE STUDY OF INSECTS 


is a cavity affording a residence for the mites. Figure 39 represents a 

section of a leaf through one of these galls. Here the leaf is seen to be 

greatly thickened at the dis- 
eased part. On the lower side 
there is an opening through 
which the mite that started 
the gall entered, and from 
which young mites developed 
in the gall can escape, in order 
to start new galls. The in- 
fested leaves become reddish 
in color but finally turn black 
and drop off. Badly infested 
trees fail to develop good fruit 
and buds are not produced for 
the succeeding crop. Apple 

trees are also badly infested by this mite. The mite can be controlled 

by spraying the trees with lime-sulphur solution in the early spring before 

the buds burst. 

Among the scavenger mites there are some that infest food products. 

Thus mites arc sometimes found in cheese, in sugar, and in preserved 

meats. 


Fig. 39. — Diagram of gall of PhyUocoples pyri: g, gall; 
normal structure of leaf; o, opening of gall; e, eggs. 
Soraur). 


n, n, 
(After 


Class DIPLOPODA 
The Millipedes or Diplopods 

The members of this class are air-breathing arthropods in which the head 
is distinct, and the remaining segments of the body form a continuous region. 
The greater number of the body-segments are so grouped that each apparent 
segment bears two pairs of legs. The antenna are short and very similar to 
the legs. The openings of the reproductive organs are paired, and situated 
behind the second pair of legs. 

The Diplopoda and the Chilopoda were formerly grouped together in 
the class, Myriapoda. But this grouping has been abandoned, because it 
has been found that the Chilopoda are more closely allied to the insects 
than they are to the Diplopoda. Owing to the very general and long 
continued use of the term Myriapoda, the student who wishes to look up 
the literature on these two classes should consult the references under 
this older name. 

The most distinctive feature of the millipedes is that which sug- 
gested the name Diplopoda for the class, the fact that throughout the 
greater part of the 
length of the body 
there appear to be 
two pairs of legs 
borne by each seg- 
ment (Fig. 40). 

This apparent 


Fig. 40. — A millipede, Spirobolus marginatus. 

doubling of the legs is due to a grouping of the segments in pairs and cither 
a consolidation of the tcrga of each pair or the non-development of one 
of them; which alternative is the case has not been definitely determined. 


INSECTS AND THEIR NEAR RELATIVES 21 

Most of our more common millipedes possess stink-glands, which 
open by pores on a greater or less number of the body-segments. These 
glands are the only means of defence possessed by millipedes, except the 
hard cuticula protecting the body. 

The millipedes as a rule are harmless, living in damp places and feed- 
ing on decaying vegetable matter; but there are a few species that occa- 
sionally feed upon growing plants. 


Class CHILOPODA 
The Centipedes or Chilopods 

The members of this class are air-breathing arthropods in which the head 
is distinct, and the remaining segments of the body form a continuous region. 
The numerous pairs of legs are not grouped in double pairs, as in the 
Diplopoda. The antennce are long and many-jointed. 
The appendages of the first body-segment are jaw- 
like and function as organs of offense, the poison 
jaws. The opening of the reproductive organs is in 
the next to the last segment of the body. 

The animals constituting the class Chilopoda 
are commonly known as centipedes. They vary 
to a considerable degree in the form of the body, 
but in all except a few forms the body-segments 
are distinct, not grouped in couples as in the dip- 
lopods (Fig. 41). They are sharply distinguished 
from the preceding class in the possession of poison- 
jaws and in having the opening of the reproduc- 
tive organs at the caudal end of the body. The 
body is usually flattened. 

Many species of centipedes are venomous. 
The poison glands open through the appendages 
of the first body-segment. These organs are leg- 
like in form and are bent forward so as to act 
with the mouth -parts. These creatures abound 
in all parts of the United States ; those which are 
found in the North are comparatively small, and 
rarely, if ever, inflict serious injury to man; but 
the larger species, which occur in the warmer re- 
gions, are unquestionably venomous. 

The centipedes are predacious, feeding on in- 
sects; they usually live under stones, logs, and 
bark. There is one species, the house centipede, 
Scutigera forceps, which has fifteen pairs of very 
long legs and which is often present running on 
the walls of dwelling houses, especially in the 
warmer regions of the United States. It hunts 
for flies and other insects and appears to be harm- 
less to man. It prefers damp situations; in 
houses it is most frequently found 'in cellars, 
bathrooms, and closets. Sometimes it becomes 
very abundant in warm, moist conservatories. 


Fig. 41. — Scutigera forceps. 


CHAPTER II 

CLASS HEXAPODA 

The Insects 

The members of this class are air-breathing Arthropoda, with distinct 
head, thorax, and abdomen. They have one pair of antennce, threee pairs of 
legs, and usually one or two pairs of wings in the adult state. The opening 
of the reproductive organs is near the caudal end of the body. 

There are about us on every side myriads of tiny creatures that are 
commonly passed unnoticed, and even when observed, they are usually 
thought to be unworthy of serious consideration. But all life is linked 
together in such a way that no part of the chain is unimportant. Fre- 
quently the action of some of these minute beings seriously affects the 
material success or failure of a great commonwealth. The introduction 
and spread of a single species of insect (the cottony-cushion scale) in 
California threatened the destruction of the extensive orchards of that 
State; thousands of trees perished. The introduction of a few individuals 
of a particular kind of lady-bug (Rodolia cardinalis), which feeds upon 
this pest and multiplies rapidly, soon checked the pest, and averted the 
disaster. 

But insects are of interest to us for other reasons than the influence 
they may have upon our material welfare ; the study of them is a fruitful 
field for intellectual growth. It is not a small matter to be able to view 
intelligently the facts presented by the insect world, to know something 
of what is going on around us. And so extensive and complex is this 
field that no one gains more than a mere smattering concerning it. 

We know as yet comparatively little about the minute structure of 
insects; the transformations and habits of the greater number of species 
have not been studied; and the blood-relationship of the various groups 
of insects is very imperfectly understood. If, therefore, one would learn 
something of the action of the laws that govern the life and development 
of organized beings, and at the same time experience the pleasure de- 
rived from original investigation, he cannot find a better field than is 
offered by the study of insects. 

But it is not necessary that one should have the tastes and leisure 
required for careful scientific investigation in order to profit by this study. 
It can be made a recreation, a source of entertainment when we are tired, 
a pleasant occupation for our thoughts when we walk. Any one can find 
out something new regarding insect architecture — the ways in which 
these creatures build nests for themselves or for their young. It is easy 
to observe remarkable feats of engineering, wonderful industry, unremit- 
ting care of young, tragedies, and even war and slavery. 

The abundance of insects makes it easy to study them. They can be 
found wherever man can live, and at all seasons. This abundance is even 
greater than is commonly supposed. The number of individuals in a 


HEXAPODA 23 

single species is beyond computation: who can count the aphid s or the 
scale-insects in a single orchard, or the bees in a single meadow? 

Not only are insects numerous when we regard individuals, but the 
number of species is far greater than that of all other animals taken 
together. The number of species in a single family is greater in several 
cases than the number of stars visible in a clear night. 

The word insect is often applied incorrectly to any minute animal; 
but the term should be restricted to those forms possessing six legs and 
belonging to the class, Hexapoda. Thus spiders, which have eight legs, 
are not insects. 

The name Hexapoda is from two Greek words: hex, six; and pous, 
foot. It refers to the fact that the members of this order differ from 
other arthropods in the possession of only six feet. 

Insects breathe by means of a system of air-tubes (tracheae) which 
extends through the body. This is true even in the case of those that 
live in water and are supplied with gill-like organs (the tracheal gills; 
see p. 39). The head is distinct from the thorax, and bears a single pair 
of antennas; in these respects they are allied to the millipedes and centi- 
pedes although they are apparently more closely related to a small group 
of animals known as symphylids of the class, Sym phyla (see "An Introduc- 
tion to Entomology" by J. H. Comstock). 

They can be easily distinguished by the number of their feet, and, 
usually, also by the presence of wings. 

The Metamorphoses of Insects 

Nearly all insects in the course of their lives undergo remarkable 
changes in form. Thus the butterfly, which delights us with its airy 
flight, was at one time a caterpillar; the bee, which goes so busily from 
flower to flower, lived first the life of a clumsy, footless grub; and the 
graceful fly was developed from a maggot. 

In the following pages considerable attention will be given to descrip- 
tions of the changes through which various insects pass. It is our wish 
in this place merely to define certain terms which are used in describing 
these changes. 

Development without metamorphosis. — In two of the orders of insects, 
the Thysanura and Collembola, the young insect just hatched from the 
egg is of the same form as the adult insect. These insects. merely grow 
larger, without any more marked change in form than takes place in our 
own bodies during our life. They are said, therefore, to develop without 
metamorphosis. 

Incomplete or gradual metamorphosis. — There are many insects which 
undergo a striking change of form during their life, although the young 
greatly resembles the adult. Thus a young locust just out from the egg 
can be easily recognized as a locust. It is of course much smaller than 
the adult, and is not furnished with wings. Still the form of the body is 
essentially the same as that of the adult (Fig. 42). (The hair-line above 
the figure indicates the natural size of the insect.) After a time rudi- 
mentary wings appear; and these increase in size from time to time till 
the adult state is reached (Figs. 43 to 47). During this development 
there is no point at which the insect passes into a quiescent state corre- 
sponding to the chrysalis state of a butterfly. Those insects which, like 


24 


THE STUDY OF INSECTS 


the locust, when they emerge from the egg resemble in form the adult, 
but still undergo some change, are said to undergo an incomplete meta- 
morphosis. In other words, after leaving the egg they do not undergo a 
complete change of form. 

There are many other insects besides locusts which have an incom- 
plete metamorphosis. For example, crickets, cockroaches, aphids, the 
true bugs, cicadas, scale- insects, et al. 

The young of three orders of insects, the stoneflics (Plecoptera) , the 
mavrlies (Ephemerida) and the dragonflies (Odonata) are adapted for 


Fig. 42. — Nymph of Melanoplus, 
first stage. (After Emerton.) 


Fig. 45. — Nymph of Melanoplus, 
fourth stage. (After Emerton.) 


Fig. 4.?. — Nymph of Melanoplus, 
second stage. (After Emerton.) 


Fig. 46. — Nymph of Melanoplus, fifth 
stage. (After Emerton.) 


Fig. 44. — Nymph of Melanoplus, 
stage. (After Emerton.) 


third 


Fig. 47. — Melanoplus, adult. 


living in the water and most of them pass through somewhat more com- 
plicated changes than do the nymphs of locusts. For these reasons 
perhaps they ought to be included in a group by themselves and desig- 
nated as having a special phase of metamorphosis; but for the sake of 
simplicity we have placed them among the insects having a gradual or 
incomplete metamorphosis. 

The nymph. — The young of all insects with incomplete metamorphoses 
are known as nymphs. The term nymph is applied to all stages of such 
insects from the time they hatch until they shed their skin for the last 
time. When a nymph first hatches it has no signs of wings; but after it 
molts once or twice one or two projections appear on each side of the 
thorax in the case of those forms in which the adult has wings. These pro- 
jections become larger and larger and more wing-like in form with each 
successive molt. 

The important feature of insects having an incomplete metamorphosis 


HEXAPODA 


25 


Fig. 48. — Eggs of insects; 1, (Ecanthus nigricornis; 
2, (Enis semidea; 3, Piezosterum subulatum; 4, Hydrometra 
martini. 


is that the wings develop externally. That is, the wings of nymphs are 
sac-like outgrowths of the body-wall which appear early and grow larger 
as already explained. 

Complete metamorphosis. — Other insects, like the bees, butterflies, 
moths, flies, and beetles leave the egg in an entirely different form from 
that which they assume when 
they reach maturity. A butter- 
fly begins its active life as a 
caterpillar. It feeds and grows, 
and when full-grown changes to 
a chrysalis. In this stage it 
has very little resemblance to a 
caterpillar. After a time there 
bursts forth from the chrysalis 
shell the butterfly, which looks 
very little like the chrysalis and 
still less like the caterpillar 
from which it came. In a 
similar way, from the egg laid 
by a fly upon a piece of meat 
there hatches, not a fly, but a 
footless, worm-like maggot. 
This when fully grown changes 
to a quiescent object corres- 
ponding to the chrysalis of a 
butterfly. Later from this ob- 
ject there escapes a winged fly like that which laid the egg. Those insects, 
like the butterflies and flesh-flics which when they emerge from the egg 
bear almost no resemblance in form to the adult insect, are said to un- 
dergo a complete metamorphosis. In other words, the change of form 
undergone by the insect is a complete one, and it passes through the fol- 
lowing stages : — 

The egg. — This is the first stage in the existence of any insect, although 
in some instances the egg remains in the body of the mother till it hatches. 
But almost always the eggs are laid by the mother insect on or near the 
food which gives nourishment to the young. Many of the most interest- 
ing habits of insects are connected with the care of the eggs by the 
parent. The eggs may have smooth oval shells; but often the shells are 
beautifully ribbed and pitted (Fig. 48), and sometimes they are orna- 
mented with spines, and are frequently exquisitely colored. 

The larva. — This is the second stage of an insect with a complete 

metamorphosis and is the form that 
hatches from the egg. Familiar ex- 
amples of larvae are caterpillars (Fig. 
49), maggots, and grubs. In fact, many 
creatures popularly known as worms 
are larvae of insects. Away from the 
ocean we find but few worms, except earthworms, leeches, "hair- 
snakes," and worm-parasites in the intestines of men and animals. The 
larval stage is devoted to growth; the sole business of a larva being 
to eat and grow. All molting, because of increased size, is done in the 
larval stage, later molts are simply for change of shape. 


Fig. 49. — A caterpillar, the larva of a moth. 


26 THE STUDY OF INSECTS 

The pupa. — This is the third stage in the life of many insects, and is 
ordinarily a period of inaction, except that rapid and wonderful changes 
go on within the body. Very few pupae, like those of mosquitoes, arc 
active. Usually pupa? have no power of moving around, but many of 
them can squirm when disturbed. When the last skin of the larva is 
thrown off the pupa is revealed ; it is an oblong object, and frequently 
apparently headless and footless. In many pupae the skin is a shiny 
covering like porcelain. If a pupa be examined closely the antennas and 

legs and wings may be seen ; these are folded 
up closely and soldered to the breast in the 
case of the moths and butterflies (Fig. 50), 
but free in case of the bees, ants, and 
beetles. 

The chrysalis. — This term is often ap- 
plied to the pupa of a butterfly. The word 

Fig. 50. - A pupa of a large moth. fe derived from a Q reek WQrd mcan ing gold, 

and came into use because of the golden dots and markings on many of the 
butterfly pupae. 

The cocoon. — Many larvae, especially those of moths, when full 
grown, spin about the body a silken case, so that when they change to 
helpless pupae they may be protected from enemies, and from rain and 
snow; these silken cases are called cocoons. They are frequently made 
within a rolled leaf (Fig. 51), or beneath grass and rubbish on the ground, 
or in cells below the ground. Some hairy caterpillars make cocoons 
largely of their own hairs, which they fasten together with a film of silk. 

The important characteristic of 
insects having a complete metamor- 
phosis is that the wings develop in- 
ternally. The wings begin to form in 
the young larvae, caterpillars of but- 
terflies, as buds of the hypodermis 
underneath the cuticula and appear 
for the first time when the last larval ^ 
skin is shed. ( 

Imago. — A fully developed or „ J , . 

-. ,, . , . 11 j • TM Fig. 51. — A large cocoon wit hm a rolled leaf. 

adult insect is called an imago. I lie 

imagos of most insects except those of the orders Thysanura and.Col- 
lembola have wings although there are many eases where wings have 
been lost through disuse. An insect never grows or molts after it reaches 
the adult stage. There is a popular belief that a small fly will grow into a 
large fly, but this is not true, for after any insect gets its perfect wings it 
can grow no larger, except that in case of females the body may be 
distended by the growth of eggs within it. While many adults cat more 
or less, it is only to sustain life, and not for growth. Indeed, many adult 
insects take very little food, and some have lost their mouth-parts 
entirely, through disuse. The adult stage usually lasts for a considerably 
shorter time than the larval or nymph stages. In fact, it seems planned 
in the economy of nature that the grown-up insects should live only long 
enough to lay eggs, and thus secure the perpetuation of the species. For 
example, mayflies live but a few days or even but a few hours, — just long 
enough, apparently, to lay their eggs and provide for the perpetuation of 
the species. 


HEXAPODA 


27 


How Insects Grow 

It has already been pointed out that a small fly does not grow into a 
large fly. No insect grows after it becomes an imago. All growth of an 
insect takes place in the young stages and larval and nymphal stages; 
and growth in these immature stages is accompanied by a shedding or 
molting of the outer skin. 

Molting. — The outer skin of a nymph or of a larva consists in large 
part of a substance known as chitin. In the young insect this outer 
skin soon becomes so firm and hard that it will not stretch enough to 


Fig. 53. ■ — Leg of May-beetle. (After Straus-Durckhenn.) 


allow for the growth of the insect. The result is that 
from time to time the skin of the young insect becomes 
too small for it and must be shed. But before this is 
done a new skin is formed beneath the old one; then the 
old skin bursts open, and the insect crawls forth, clothed 
in a soft skin, which stretches to accommodate the in- 
creased size of the individual. Very soon, however, this 
new skin becomes hardened, and after a time it in turn 
must be shed. This shedding of the skin is termed molt- 
ing, and the cast skin is sometimes referred to as the 
exuvicz. Insects differ greatly as to the number of times 
they molt: many species molt only four or five times, 
known to molt more than twenty times. Figure 52 


Fig. 52. — Exuviae 
nymph of dragonfly. 

while others are 

represents the cast skin of a dragonfly clinging to a reed. 


The External Anatomy of Insects 

The subject of insect anatomy is separated into two divisions: one, 

treating of the structure of the 
body- wall or skeleton ; the other, 
of the internal organs. The for- 
mer is termed external anatomy; 
the latter, internal anatomy. 

In our own bodies we find a 
central framework or skeleton, 
about which are arranged the 
muscles, blood-vessels, nerves, 
and other organs. But insects 
are constructed on an entirely 
different plan; with them the 
supporting skeleton is outside, 
and the muscles, nerves, and 
— a section of the body-waii of an insect: other organs are within this 

/;, hypodermis; bm, basement membrane; 1 1 / rrvi tj?c u 

d, dermis; tr, tdchogen; s, seta. skeleton. The difference can be 


Fig. 54- 
<-, cuticula; 
e, epidermis. 


28 


THE STUDY OF INSECTS 


well seen if the figure showing the internal structure of the leg of a may- 
beetle (Fig. 53) be compared with one of our own limbs, either arm or leg. 

The body of an insect is built on the same 

plan as arc its legs. The outside of the body 

is more or less firm, and this firm outer wall 

supports the muscles and other organs, thus 

The skeleton is therefore, in general outline, a 


Fig. 55- — A Larva. 


Fig. 56. — An 

earwig. 


serving as a skeleton 
hollow cylinder. 

The outer body-wall is composed of three layers: (1) an outer pro- 
tective layer, the cuticula; (2) a middle layer, the hypodermis; 
and (3) an inner delicate thin layer, the basement membrane 
(Fig. 54). The cuticula is a tough sheet of chitin often hard- 
ened by the deposition in it of other substances. 

The cuticula is not hardened throughout but remains soft 
and flexible at certain transverse indentations running around 
the body. These soft places in the cuticula mark the divi- 
sions between the ring-like portions of the body called seg- 
ments. 

In this way provision is made for the various motions of 
the body. The ring-like nature of the segments of the body 
is best seen in larvae (Fig. 55), and in the abdomen of an 
adult insect (Fig. 56). The movements of the legs, antennae, and certain 
other appendages are provided for in the same way; each one is a cylin- 
der made up of several segments, and be- 
tween these segments the wall of the 
cylinder remains flexible. 

When a single segment of the body is 
examined, its cuticula is not found to be 
side-view of locust with wings a continuous ring, but is seen to be made 
up of several portions more or less mov- 
able upon each other. Such a hardened portion of the cuticula is termed 
a sclerite. 

The sclerites constitute the greater part of the cuticula, the soft 
membranous portions separating them being in 
most cases narrow. Usually these narrow por- 
tions are mere lines; they are then called su- 
tures. 

Frequently the sutures become entirely ef- 
faced. We are therefore often unable to distin- 
guish certain sclerites in one species of insect 
which we know to exist in another. In such cases 
the effaced sutures are said to be obsolete. 

If the central portion or thorax of an adult 
insect be examined, numerous sclerites and su- 
tures can be observed (Fig. 57). 

The subject of external anatomy of insects 
consists very largely in a study of the sclerites of 
which the different segments of the body and of 
its appendages are composed. This part of the 
subject is quite difficult, and will not be discussed 
here. It is treated, however, in the discussion 
of the characters used in the classification of the Coleoptera given on 


Fig. 58. — Wasp, with head, 
thorax, and abdomen separated. 


HEXAPODA 


29 


pages 128 to 130. These pages should be carefully studied before 
attempting to use the table that follows them. 

The segments of the body in a fully developed insect are grouped into 
three regions: head, thorax, and abdomen (Fig. 58). In the larval state 
this grouping of the segments is not well shown. 


The Head and its Appendages 

The head is the first of the three regions of the body formed of several 
body-segments grown together. 

The head bears the compound eyes, the simple eyes or ocelli, the an- 
tennae, and the mouth-parts. 

The compound eyes. — On each side of the head of an adult insect is 

an organ, which is 
recognized at once as 
an eye. But when 
one of these eyes is 
examined with a mi- 
croscope it is found 
to present an appear- 
ance very different 
from that of the eye 
of higher animals; its surface is divided 
into a large number of six-sided divisions 
(Fig. 59). A study of the internal struc- 
ture of this organ has shown that each of 
these hexagonal divisions is the outer 
^^npvC- end of a distinct portion or element of 

-| / II \ ^ the eye (Fig. 60). Hence what at first 

"X^vJLy^" a PP ears to De a single eye is really an 
1§Nf€* organ cc 


*/. 


Fig. 59. — Part of surface 
of compound eye, greatly 
enlarged. 


r-jpv 


omposed of hundreds of distinct 
structures; it is termed, therefore, a com- 
pound eye. Each of the small elements 
of which a compound eye is composed is 
termed an ommatidium (plural ommati- 
dia). The number of ommatidia of which 
a compound eye is composed varies 
greatly: there may be not more than 
fifty, as in certain ants, or there may be 
many thousand, as in a butterfly or a 
dragonfly. Compound eyes are not found 
in larvae, though they may possess a group 
of simple eyes on each side of the head. 
The simple eyes. — In addition to the 
compound eyes, many adult insects pos- 
sess simple eyes. These are situated be- 
tween the compound eyes. They vary in 
number from two to three; the most 

common number is three (see Fig. 58). The simple eyes are termed ocelli. 
Nymphs also possess ocelli but in the case of most larvae there are 

simple eyes which are different in origin from the ocelli of adult insects. 
The antennae. — The antennas are a pair of jointed appendages artic- 


FlG. 60. — An ommatidium of Machilis 
c, cornea; ky, corneal hypodermis; cc, crystal- 
line-cone-cells; :', iris-pigment cells; r, retin- 
ula cells; rh, rhabdom; b, basement mem- 
brane; ap, accessory pigment cells. 


3° 


THE STUDY OF INSECTS 


ulated with the head in front of the eyes or between them. They vary 
in form. In some insects they are thread-like, consisting of a series of 
similar segments; in others certain segments are greatly modified in 
form. 

The various forms of antennas arc designated by special terms. The 
more common of these forms are represented in Figure 61. These are as 
follows: 

i. Setaceous or bristle-like, in which the segments are successively 
smaller and smaller, the whole organ tapering to a point. 

2. Filiform or thread-like, in which each segment is of nearly 


Various forms of an- 


Fig. 62. — Mouth-parts of the red- 
legged Locust. 


uniform thickness throughout its length; and the antenna as a whole 
tapers gradually, if at all, towards the tip. 

3. Moniliform or necklace-form, in which the segments are more or 
less globose, suggesting a string of beads. 

4. Serrate or saw-like, in which the segments are triangular, and pro- 
ject like the teeth of a saw. 

5. Pectinate or comb-like, in which the segments have long processes 
on one side, like the teeth of a comb, or on both sides, like a feather. 

6. Clavatc or club-shaped, in which the segments become gradually 
broader, so that the whole organ assumes the form of a club. 

7. Capitate or with a head, in which the terminal segment or seg- 
ments form a large knob. 

8. Lamellate in which the segments that compose the knob are ex- 
tended on one side into broad plates. 

The mouth-parts . — No organs in the body of an insect vary in form 
to a greater degree than do the mouth-parts. Thus with some the 
mouth is formed for biting, while with others it is formed for sucking. 
Among the biting insects some are predacious, and have jaws fitted for 
seizing and tearing their prey; others feed upon vegetable matter, and 


HEX APOD A 31 

have jaws for chewing this kind of food. Among the sucking insects the 
butterfly merely sips the nectar from flowers, while the mosquito needs a 
powerful instrument for piercing its victim. In this place the typical 
form of the mouth-parts as illustrated by the biting insects is described. 
The various modifications of it presented by the sucking insects are 
described later, in the discussion of the characters of those insects. 

In the biting insects, the mouth-parts consist typically of an upper 
lip, the labrum (Fig. 62, 8); an under lip, the labium (Fig. 62, 12); and 
two pairs of jaws between them. These jaws open sidewise, instead of in 
a vertical direction, as do the jaws of the higher animals. The jaws of 
the upper pair are called the mandibles (Fig. 62, 10); the lower pair, the 
maxilla; (Fig. 62, 11). There may be also within the mouth one or two 
tongue-like organs, the cpipharynx and hypopharynx (Fig. 62, 13). The 
epipharynx is attached to the upper wall of the cavity of the mouth, 
and the hypopharynx to the lower. The position of the hypopharynx is 
quite analogous, therefore, to that of our tongue. 

The mandibles vary much in form, but usually each consists of a 
single sclerite. The maxillae of biting insects, on the « 

other hand, are very complicated organs, each com- ; W^*^1 

posed of several scleritcs. Each maxilla bears an appen- ^nH^, /»\' 
dage consisting of several segments; these appendages f^EU^i0^ 
are termed the maxillary palpi. In the maxillae of cer- ^fflrg^ 
tain biting insects, as the grasshoppers and the ground ^H^f 

beetles, there is an appendage usually consisting of two *^ Bp 

segments: this is the galea or outer lobe. In some of Wt~4 

these insects, as the ground-beetles and the tiger-beetles, *& 

the galea is shaped like a plapus, and thus there appear Fre. 63. — Maxilla of 
to be two pairs of maxillary palpi (Fig. 63). The la- 
bium is furnished with a pair of jointed appendages; these are the labial 
palpi (Fig. 62, 12, d). 

The Thorax and its Appendages 

The thorax is the second or intermediate region of the body; it is the 
region that bears, in the adult insect, the organs of locomotion, the legs, 
and the wings when they are present. This region is composed of three 
of the body-segments more or less firmly joined together; the segments 
are most readily distinguished by the fact that each bears a pair of legs. 
In winged insects, the wings are borne by the second and third segments. 
The first segment of the thorax, the one next to the head, is named the 
prothorax; the second thoracic segment is the mesothorax; and the third, 
the metathorax. 

The legs. — Each leg consists of the following parts, beginning with 
the one next to the body (see Fig. 64) : coxa, trochanter, femur, tibia, and 
tarsus. Each of these parts consists of a single segment except that in 
certain Hymenoptera the trochanter consists of two segments (Fig. 
64, t), and in most insects the tarsus consists of several segments. The 
number of segments of the tarsus usually varies from one to^ five. Fre- 
quently the first segment of the tarsus is much longer than either of the 
other segments, and it may also differ greatly in form from them ; under 
such circumstances it is sometimes designated the metatarsus (Fig. 64). 
The last segment of the tarsus usually bears one or two claws. 


32 


THE STUDY OF INSECTS 


Fig. 64. — Legs of insects: A, wasp; B, ichneu- 
mon-!ly; C, bee; c, coxa; tr, trochanter; /, femur; 
/;', tibia; la, tarsus; met., metatarsus. 


On the ventral surface of the segments of the tarsus in many insects 
are cushion-like structures termed pulvilli. In many insects the pulvilli 
of the last segment of the tarsus are circular pads beneath the tarsal 
claws. In most descriptive works these are referred to as the pulvilli, 
even though the other pulvilli are well developed. 

The pulvilli of some insects, notably those of the Diptera, bear fine, 

hollow hairs, called tenent hairs, from 
which an adhesive fluid exudes that 
enables the insect to walk on the 
undersides of objects. 

The wings. — The two pairs of 
wings are borne by the mesothorax 
and metathorax, but either or both 
pairs may be wanting. Thus the 
flies, or Diptera, have only the first 
pair of wings fitted for flight, the 
second pair being represented by a 
pair of knobbed threads; and with 
the earwigs and beetles each of the 
first pair of wings is hard and to- 
gether they form a cover for the hind 
pair. 

In form an insect's wing is a large, 
membranous, leaf-like appendage, 
which is thickened along certain lines. These thickened lines are termed 
the veins or nerves of the wing; and their arrangement is described as the 
venation or neuration of the wings. The thin spaces of the wings which 
are bounded by the veins are called cells. When a cell is completely 
surrounded by veins it is said to be closed; but when it extends to the 
margin of the wing it is said to be open. 

The wings of different insects vary greatly in structure, and thus 
afford excellent distinctions for the 
purposes of classification. The vari- 
ous parts of the wing have, there- 
fore, received special names. There 
is considerable lack of uniformity 
among entomologists as to the names 
applied to these parts; but we have 
adopted the set of terms defined be- 
low as representing the best usage. 

An insect's wing is more or less 
triangular in outline; it therefore 
presents three margins: the costal 
margin, or costa (Fig. 65, a-b); the 
outer margin (Fig. 65, b-c); and the inner margin (Fig. 65, c-d). 

The angle at the base of the costal margin (Fig. 65, a) is the humeral 
angle; that between the costal margin and the outer margin (Fig. 65, b) 
is the apex of the wing; and the angle between the outer margin and 
the inner margin (Fig. 65, c) is the anal angle. 

There have been many different sets of names applied to the veins of 
the wings. Not only have the students of each order of insects had a 
peculiar nomenclature, but in many cases different students of the same 


Fig. 65. 

angles. 


Diagram of a wing showing margins and 


HEXAPODA 


33 


order of insects have used different sets of terms. This condition of 
affairs was incident to the beginning of the science, the period before 
the correspondence of the veins in the different orders had been worked 
out. But now the time has come when it seems practicable to apply a 
uniform nomenclature to the wing veins of all orders; and the following 
set of terms is proposed for that purpose. 

The principal veins of the wing, those that arise at or near the base 
of the wing, are termed, beginning with the one lying on the costal mar- 
gin, the costa, the subcosta, the radius, the media, the cubitus, and the 
anal veins. The radius, media, and cubitus are usually branched, and 
there may be several anal veins. 

In addition to the principal or longitudinal veins, there may be a 
greater or less number of cross-veins — veins extending transversely from 
one longitudinal vein to another. 

The principal veins may be designated by numbers as well as by 
names ; the following table indicates the correspondence of the names and 
numbers : 


Costa = vein I. 
Subcosta = vein II. 
Radius = vein III. 
Media = vein V. 


Cubitus = vein VII. 
ist anal vein = vein VIII. 
2d anal vein = vein IX. 
3d anal vein = vein XI. 


It was formerly believed that in certain insects three other longitu- 
dinal veins were present; these were numbered IV, VI, and X respec- 
tively; hence these numbers are omitted in the above table. 

At the time the first edition of this book was written, it was thought 
best to designate the veins by numbers; but owing to a lack of uniform- 
ity in the numbering of the veins by different writers, it is now clear that 
the names are to be preferred. In the lettering of figures, abbreviations 
of the names can be used as is done in Figure 66. 


idA 

Fig. 66. — Wing of a fly, Antsopus. 


The divisions of a branched vein are numbered, beginning with the 
one nearest the costal margin of the wing; and these numbers are in- 
dicated by sub-figures. For example, the five branches of the typical 
radius are designated thus, Ri, R 2 , R3, R4, Rs- 

When two or more branches of a branched vein coalesce, the com- 
pound vein is designated by an expression indicating this coalescence, as 
R2+3. In this way it is possible to indicate some of the changes that 
have taken place in the development of the species; and to make use of 


34 


THE STUDY OF INSECTS 


them in working out the classification of the group to which the species 
belongs. 

The cells of the wing are designated by applying to each the number 
or the abbreviation of the name of the vein that forms its cephalic (front) 
margin. In Figure 06 the veins are designated by letters at the margin 
of the figure; the cells by letters within the figure. When a cell is 
divided by a cross- vein the parts are numbered, as in the case of cell M 2 
in Figure 66. 

The Abdomen and its Appendages 

The abdomen is the third or caudal region of the body. Its segments 
are more simple, distinct, and ring-like than those of the other regions. 
The number of segments of which it appears to be composed varies 
greatly. In the cuckoo-flies {Chrysididaz) there are usually only three or 
four visible, while in many other insects nine appear. Except in the 
lowest order of insects (Thysanura) the abdomen of the adult bears no 
locomotory appendages. But many larvas have fleshy appendages which 
aid in locomotion: these are termed prolegs. In the adult the end of the 
body in many families is furnished with jointed filaments — the cerci, and 
caudal setce. Frequently also the body is furnished in the male with 
organs for clasping — the claspers; and in the female with saws, piercers, 
or borers — the ovipositor. In the female of certain insects there is a 
sting, a modified ovipositor, which is used as an organ of defence; and 
the abdomen of plant-lice and certain other insects bears a pair of tubes 
or tubercles, through which a wax-like material is excreted: these are 
termed cornicles, or siphuncles; see page 115. 


The Internal Anatomy of Insects 

As has been shown in the preceding pages, the body-wall serves as a 
skeleton, being hard, and giving support to the other organs of the body. 
This skeleton may be represented, therefore, as a hollow cylinder. We 
have now to consider the arrangement and the general form of the organs 


Fig. 67. — Diagram showing the relation of the internal organs. 

contained in this cylinder. For the details of the structure of the internal 
organs the student is referred to more special works. 

The accompanying diagram (Fig. 67), which represents a vertical, 
longitudinal section of the body, will enable one to gain an idea of the 
relative position of some of the more important organs. The parts shown 
in the diagram are as follows: the body-wall, or skeleton (s); this is 
made up of a series of overlapping segments; that part of it between the 
segments is thinner, and is not hardened, thus remaining flexible and 
allowing for the movements of the body. Just within the body-wall, 


THE STUDY OF INSECTS 

PLATE II 


Internal Anatomy of a Caterpillar (Cossus ligniperda). 

Fig. 4. — Caterpillar opened on the ventral middle line. Fig. 5. — Caterpillar opened on the dorsal 
middle iine. 1, principal longitudinal tracheae; 2, central nervous system; 3, aorta; 4, longitudinal 
dorsal muscles; 5, longitudinal ventral muscles; 6, wings of the heart; 7, tracheal trunks arising near 
spiracles; 8, reproductive organs; o, vertical muscles; 10, last abdominal ganglion. (After Lyonet.) 


THE STUDY OF INSECTS 

PLATE III 


Internal Anatomy of a Cockroach (Periplaneta orientalis). 

a, antennae; 6i, bi, ft,?, legs; c, anal cerci; d, ganglion on recurrent nerve upon the crop; 

e, salivary duct; /, salivary bladder; g, gizzard; h, hepatic cceca; i, mid-intestine; /, Malpig- 

hian vessels; k, small intestine; /, large intestine; m, rectum; », first abdominal ganglion; o, ovary; 
p, sebaceous glands. (From Rolleston.) 


HEX APOD A 35 

and attached to it, are represented a few of the muscles (ra); it will be 
seen that these muscles are so arranged that the contraction of those on 
the lower side of the body would bend it down, while the contraction of 
those on the opposite side would act in the opposite direction. The 
alimentary canal (a) occupies the centre of the body, and extends from 
one end to the other. The heart (//) is a tube lying between the ali- 
mentary canal and the muscles of the back. The central part of the 
nervous system (n) is a series of small masses of nervous matter con- 
nected by two longitudinal cords: one of these masses, the brain, lies in 
the head above the alimentary canal; the others are situated, typically 
one in each segment, between the alimentary canal and the layer of 
muscles of the ventral side of the body; the two cords connecting these 
masses, or ganglia, pass one on each side of the oesophagus to the brain. 
The reproductive organs (r) lie in the cavity of the abdomen and open 
near the caudal end of the body. The respiratory organs are omitted 
from this diagram for the sake of simplicity. 

The muscular system. — We find in insects a wonderfully large number 
of muscles. Those that move the segments of the body form several 
layers just within the body-wall. The two figures on Plate II represent 
two caterpillars which have been split open lengthwise, one on the middle 
line of the back and one on the opposite side ; in each case the alimentary 
canal has been removed, so that only those organs that are attached 
quite closely to the body-wall are left. From a study of these figures 
some idea can be obtained of the number and arrangement of these 
muscles. It should be borne in mind, however, that only a single layer of 
muscles is represented in these figures — the layer which would be seen 
if a caterpillar were opened in the way indicated. When these muscles 
are cut away many other muscles are found extending obliquely in 
various directions between these muscles and the body-wall. 

The muscles of insects appear very differently from those (the lean 
meat) of higher animals. In insects the muscles are either colorless and 
transparent, or yellowish- white ; and they are soft, almost of a gelatinous 
consistency. The fibers of insect muscles are usually if not always of the 
striated type. 

As a rule, the muscles of insects are composed of many distinct fibres 
which are not enclosed in ten- 
dinous sheaths as with verte- 
brates. But the muscles that 
move the appendages of the 
body are furnished with a ten- 
don at the end farthest from the 

bnHv (Pier f\0>\ ^ IG ' ^ — ^eg °^ May-beetle. (After Straus-Durckheim.) 

Notwithstanding the soft and delicate appearance of the muscles 
of insects, they are really very strong. 

The alimentary canal. — The typical position of this is represented in 
the diagram (Fig. 67) ; and on Plate III, illustrating the anatomy of a 
cockroach, its form in that insect is shown. In larvae it is a nearly 
straight tube, extending from one end of the body to the other. But in 
adult insects it is usually much longer than the body, and is consequently 
more or less folded. It is composed of parts differing in form and use. 
To these parts names have been given similar to those used to designate 
the corresponding parts in higher animals; thus we distinguish a pharynx. 


36 


THE STUDY OF INSECTS 


an oesophagus, sometimes a crop, sometimes a gizzard, a stomach, a small 
intestine, and a large intestine. 

The adipose tissue, or fat. — On opening the body of an insect, espe- 
cially of a larva, one of the most conspicuous things to be seen is fatty 
tissue, in large masses. These often completely surround the alimentary 
canal, and are held in place by numerous branches of the tracheae with 
which they are supplied. Other and smaller masses of this tissue adhere 
to the inner surface of the abdominal wall, in the vicinity of the nervous 
system, and at the sides of the body. In a full-grown larva of Corydalus 
cornutus the adipose tissue is often greater in bulk 
than all of the other organs found inside of the mus- 
cular walls of the body. In adult insects it usually 
exists in much less quantity than in larvae. 

The circulatory system. — In insects the circula- 
tory system is not a closed one, the blood flowing in 
vessels during only a part of its course. The greater 
part of the circulation of this fluid takes place in the 
cavities of the body and of its appendages, where it 
fills the space not occupied by the internal organs. 

Almost the only blood-vessel that exists in insects 
lies just beneath the body-wall, above the alimentary 
canal (Fig. 67, h). It extends from near the caudal 
end of the abdomen through the thorax into the 
head. That part of it that lies in the abdomen is 
the heart; the more slender portion, which traverses 
the thorax and extends into the head is the aorta. 
On each side of the heart, there is a series of 
triangular muscles extending from the heart to the 
lateral wall of the body. These constitute the dorsal 
diaphragm or the wings of the heart. 

The heart is a tube, which is usually closed at its 
posterior end; at its anterior end it is continuous 
with the aorta. The heart is divided into chambers 
(Fig. 69). The number of these chambers varies 
greatly in different insects; in some, there is only 
one, in others, as in the cockroach, there are as many 
as thirteen, but usually there are not more than 
eight. The blood is admitted to the heart through slit-like openings, the 
ostia of the heart; usually there' is a pair of ostia in the lateral walls of each 
chamber. Each ostium is furnished with a valve-like structure which 
closes it when the chamber contracts. 

When a heart consists of several chambers, they contract one after 
another, the wave of contraction passing from the caudal end of the heart 
forwards. As the valves between the chambers permit the blood to move 
forward but not in the opposite direction, the successive contractions of 
the chambers cause the blood received through the ostia to flow toward 
the head, into the aorta. The blood flows from the open, cephalic end 
of the aorta and passes in quite definite streams to the various parts of 
the body-cavity and into the cavities of the appendages. These streams, 
like the ocean currents, have no walls but flow in the spaces between 
the internal organs. After bathing these organs, the blood returns to the 
sides of the heart, which it enters through the ostia. 


Fig. 69. — Heart of May- 
beetle (after Straus Durck- 
heim): a, lateral aspect of 
aorta; b, interior of heart 
showing valves; c, ventral 
aspect of heart and wins- 
muscles — the muscles are 
represented as cut away 
from the caudal part of the 
heart; d, dorsal aspect of 
heart. 


HEXAPODA 


37 


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The blood consists of two elements, a fluid plasma and cells similar to the 
white corpuscles of the blood of vertebrates, the leucocytes. It differs greatly 
in appearance from the blood of vertebrates, on account of the absence of red 
blood corpuscles. In most insects the blood plasma is colorless ; but in many- 
species it has a yellowish, greenish, or reddish color. 
The blood receives the products of digestion of 
food, which pass in a liquid form, by osmosis, through 
the walls of the alimentary canal. On the other 
hand it gives up to the tissues which it bathes the 
materials needed for their growth. In insects oxy- 
gen is supplied to the tissues and gaseous wastes 
are removed chiefly by the respiratory system and 
not by means of the blood as in vertebrates. 

The nervous system. — The central part of the 
nervous system consists of a ganglion in the head 
above the oesophagus, and of a series of double 
ganglia, typically one for each segment of the body, 
lying on the floor of the body cavity, and connected 
by two longitudinal cords. In the head, one of these 
cords passes on each side of the oesophagus, from 
the brain to another ganglion in the head below the 
oesophagus, thus forming a nervous collar about the 
alimentary canal. From each ganglion nerves arise, 
which supply the adjacent parts; and from the 
thoracic ganglia nerves extend to the legs and wings. 
This series of ganglia is really a double one; but 
the members of each pair of ganglia are more or less 
closely united on the middle line of the body, and 
often appear as a single ganglion. Figure 70 gives a general view of the 
central nervous system of Corydalus cornutus. 

In addition to the central nervous system there are two sympathetic 
nervous systems and the peripheral sensory nervous system, the latter 

composed of a network of fine 
nerves all around the body just 
beneath the hypodermis of the 
body walls. 

How insects breathe — The 
respiratory system. — A com- 
mon mistake made by begin- 
ners in the study of Entomology is to suppose that insects breathe through 
the mouth as do the higher animals. Many a beginner has carefully 
poured chloroform on the head of an insect in the expectation of killing it 
in that way, and has been surprised at his poor success. 

The truth is, insects breathe through their sides. If an insect be 
carefully examined, there can be found along the sides of the body a 
series of openings (Fig. 71). These are the openings through which the 
air passes into the respiratory system and are termed spiracles. 

The number of spiracles varies greatly in different insects. There is, 
however, never more than one pair on a single segment of the body. 
They do not occur on the head, but are borne by each of the last two tho- 
racic segments., and by the first eight abdominal segments. Thus ten seg- 
ments may bear spiracles, but usually one or more segments lack them. 


Fie. 70. — 

of Corydalus 


Nervous system 
(After Leidy.) 


Fig. 71. — Side-view of locust with wings removed. 


38 


THE STUDY OF INSECTS 


Fig. 72. — Tracheal 
system of cockroach. 
The alimentary canal re- 
moved to show the ven- 
tral tracheal communica- 
tions. (After Miall and 
Denny.) 


These spiracles are either simple openings into the respiratory system, 
or are provided with valves, sieves, or fringes of hair for the exclusion of 
dirt. They lead into a system of air-tubes termed trachea. The accom- 
panying figure will indicate the distribution of the main trunks of these 
trachea? in a cockroach (Fig. 72). There is a short trunk 
arising from each spiracle; these are all connected to- 
gether by a large longitudinal trunk on each side of the 
body, and by numerous transverse trunks. From these 
large tracheae there arise a great number of smaller ones, 
not shown in the figure, which branch and subdivide 
and extend to all parts of the body. Connected to the 
tips and sides of these small tracheae are minute tubes 
called tracheoles. The tracheoles appear to be ultimately 
connected with the various tissues and it is through these 
that air reaches the tissues of the body. 

Although insects are, strictly speaking, air-breathing 
animals, many of them, as is well known, live in the 
water. The study of the ways in which aquatic insects 
breathe is a very interesting one ; it presents to us many 
wonderful modifications of structure. Some of the 
more common of these are described in subsequent pages 
of this book; in this place we can only make a few 
generalizations. 

The various modes of respiration of aquatic insects may be classified 
under two heads: first, those in which the insects obtain air from above 
the surface of the water; second, those in which the insects breathe the 
air that is mechanically mixed with the water. 

With many aquatic in- 
sects the spiracles open be- 
neath the wings, which are 
folded upon the abdomen. 
The insect, by coming to the 
surface of the water and 
lifting the tips of its wings, 
forms a cavity beneath them, 
into which the air rushes. 
The insect can then swim 
through the water, carrying 
this air with it in a position 
where it can be respired. 
When the air becomes im- 
pure, the insect rises to the 
surface, forces out the air 
from beneath its wings, and 
takes in a new supply. Wa- 
ter beetles and aquatic bugs 
afford familiar examples of this mode of respiration. 

Some insects are provided with long tubes connected with their spira- 
cles, by means of which they can draw their supply of air from above 
the surface of the water while they crawl upon the bottom of shallow 
ponds. Our most common illustrations of this are bugs of the family 
Nepidce; but the most remarkable development of this kind is exhibited 


R 


Fig. 7.?. — Tracheal gill of a damselfly: A, en- 
tire gill showing the tracheae; B, part of gill more 
magnified, showing both tracheae (T) and tra- 
cheoles (I). 


HEX APOD A 39 

by certain dipterous larvae of the family Syrphidoe, known as rat-tailed 
maggots. 

Although there are many insects that live in the water and draw their 
supply of air from above it, many aquatic insects breathe, as do fishes, 
the air that is mixed with the water. This is accomplished by organs 
known as tracheal gills. These are hair-like or more or less plate-like 
expansions of the body-wall, abundantly supplied with tracheae (Fig. 73). 
These tracheae divide and subdivide, and their terminations or fine 
branches, tracheoles, are separated from the water that bathes the organ 
only by its thin walls. In this way the air contained in the tracheae is 
separated from the air in the water only by a delicate membrane, which 
admits of the transfer of gases between them. It will be observed that 
the difference between a tracheal gill and a true gill (as of fishes, Crus- 
tacea, etc.) is that the true gill is supplied with vessels containing blood, 
which is purified by being brought in contact with the air in the water, 
while the tracheal gill is supplied with tracheae containing air to be puri- 
fied. 

Tracheal gills are usually borne by the abdomen, sometimes by the 
thorax, and in case of some stoneflies by the head. They pertain al- 
most exclusively to the immature stages of insects; but stoneflies of the 
genus Pteronarcys retain them throughout their existence. 

Tracheal gills vary greatly in form; in Corydalus they are hair-like, 
and occur in tufts near the lateral margins of the abdominal segments; 
in the caddice-worms they are thread-like, more or less branched, and 
irregularly distributed over the surface of the abdomen; and in certain 
damselflies they are in the form of large plate-like caudal appendages. 

( Fi g- 73-) . ... 

The reproductive organs. — The reproductive organs are situated in 

the abdomen, as represented in Figure 67. There is a set on each side 
of the body; but the two sets usually open by a common tube near the 
caudal end of the body. In the mayflies and in the earwigs, however, 
the reproductive organs of each side have a distinct opening. Thus may- 
flies are often found with two bunches of eggs projecting from the caudal 
end of the body. 

All insects are developed from eggs; but there are some apparent 
exceptions. Thus many flies retain their eggs until after they are 
hatched, and in some flies the young attain a considerable development 
before they are born. In the plant-lice (Aphtdidce) there is a remarkable 
alternation of reproduction. This is described more fully in the account 
of that family. 

The Subclasses and Orders of the Hexapoda 

The class, Hexapoda, is divided into two subclasses, the Apierygota 
and the Pterygota. The primitive insects were undoubtedly wingless; 
and there are two orders of living insects, the Thysanura and the Col- 
lembola, which are still wingless. These orders constitute the subclass 
Apterygota. All other insects are believed to have descended from 
winged ancestors and are therefore placed in the subclass, Pterygota. 
Some of the forms in this subclass, for example the bird-lice, the sucking 
lice and the fleas have lost their wings during their sedentary parasitic 
lives but this wingless condition is certainly an acquired one. 


4 o THE STUDY OF INSECTS 

We have divided the Ilexapoda in this work into twenty-five orders 
and have arranged them in a linear series as must be done in a simple 
text-book; for it is impossible to indicate in a satisfactory way either the 
relation of the orders to each other or the relative rank of the orders. 
An effort is made to place near together closely allied orders, and to 
treat first those that are more simple or primitive or generalized in 
structure, and last those that are more specialized. But this plan could 
be fully carried out only by having several parallel columns on the pages 
of the book, each representing a distinct line of descent, an arrangement 
which, to say the least, is impracticable. 

The list below indicates the sequence in which the orders are discussed 
in the following chapters. 

subclass apterygota. — Wingless insects in which the wingless condition is 
believed to be a primitive one, there being no indication that they have descended from 
winged ancestors. 

1. order thysanura. — The Bristle-tails, p. 45 

2. order collembola. — The Spring-tails, p. 47 

subclass pterygota. — Winged insects and wingless insects in which the wing- 
less condition is believed to be an acquired one; i.e., those insects that have de- 
scended from winged ancestors. 

3. order orthoptera. — The Cockroaches, Crickets, Grasshoppers, and others. 

P- 49 

4. order zoraptera. — The genus Zorotypus. p. 62 

5. order isoptera. — The Termites or White Ants. p. 63 

6. order neuroptera. — The Dobson, Aphis-lions, Ant-lions, and others, p. 66 

7. order ephemerida. — The Mayflies, p. 74 

8. order odonata. — The Dragonflies and the Damselflies. p. 77 

9. order plecoptera. — The Stonefhes. p. 81 

10. order corrodentia. — The Psocids. p. 83 

11. order mallophaga. The Bird-lice. p. 85 

12. order embiidina. — The Embiids. p. 87 

13. order thysanoptera. — ■ The Thrips. p. 89 

14. order anoplura. — The Lice. p. 92 

15. order hemiptera. — The True Bugs. p. 94 

16. order homoptera. — The Cicadas, Leafhoppers, Aphids, Scale-bugs, and others. 

p. 109 

17. order dermaptera. — The Earwigs, p. 125 

18. order coleoptera. — The Beetles, p. 127 

19. order strepsiptera. — The Twisted Winged Insects, p. 176 

20. order mecoptera. — The Scorpion-flies, p. 178 

21. order trichoptera. — The Caddice-fties. p. 180 

22. order lepidoptera. — The Moths, the Skippers, and the Butterflies, p. 183 

23. order diptera. — The Flies, p. 286 

24. order siphonaptera. — The Fleas, p. 326 

25. order hymenoptera. — The Bees, Wasps, Ants, and others, p. 329 

TABLE FOR DETERMINING THE ORDERS OF THE HEXAPODA 

This table is merely intended to aid the students in determining to which of 
the orders a specimen that he is examining belongs. No effort has been made to 
indicate in the table the relation of the orders to one another. 
A. Winged. (The wing-covers, Elytra, of beetles and of earwigs are wings.) 
B. With two wings. 

C. Wings horny, leathery, or parchment-like. 

D. Mouth-parts formed for sucking. Wings leathery, shortened, or mem- 
branous at the tip. p. 94 Hemiptf.ra 

DD. Mouth-parts formed for biting. Jaws distinct. 


HEXAPODA 41 

E. Wings horny, without veins. Hind legs not fitted for jumping, p. 127 

COLEOPTERA 

EE. Wings parchment-like with a network of veins. Hind legs fitted for 
jumping, p. 49 . . Orthoptera 

CC. Wings membranous. 

D. Abdomen with caudal filaments. Mouth-parts vestigial. 

E. Halteres wanting, p. 74 Ephemerida 

EE. Halteres present (males of Coccidae). p. 109 Homoptera 

DD. Abdomen without caudal filaments. Halteres in place of second wings. 

Mouth-parts formed for sucking, p. 286 Diptera 

RB. With four wings. 
C. The two pairs of wings unlike in structure. 

D. Fore wings reduced to slender club-shaped appendages; hind wings fan- 
shaped with radiating veins. Minute insects, p. 176 Strepsiptera 

DD. Front wings leathery at base, and membranous at tip, often overlapping. 

Mouth-parts formed for sucking, p. 94 Hemiptera 

DDD. Front wings of same texture throughout. 

E. Front wings horny or leathery, being veinless wing-covers. {Elytra.) 
F. Abdomen with caudal appendages in form of movable forceps, p. 125 

Dermaptera 

FF. Abdomen without forceps-like appendages, p. 127 Coleoptera 

EE. Front wings leathery or parchment-like with a network of veins. 
F. Under wings not folded; mouth-parts formed for sucking. 

G. Beak arising from the front part of the head. p. 94 .... Hemiptera 
GG. Beak arising from the hind part of the lower side of the head. 

p. 109 Homoptera 

FF. Under wings folded lengthwise. Mouth-parts formed for chewing. 

p. 49 Orthoptera 

CC. The two pairs of wings similar, membranous. 

D. Last joint of tarsi bladder-like or hoof-like in form and without claws. 

Wings with fringe of long hairs, p. 89 Thysanoptera 

DD. Last joint of tarsi not bladder-like. 

E. Wings entirely or for the greater part clothed with scales. Mouth-parts 

formed for sucking, p. 183 Lepidoptera 

EE. Wings naked, transparent, or thinly clothed with hairs. 

F. Mouth-parts arising from the hinder part of the lower surface of the 
head, and consisting of bristle-like organs inclosed in a jointed sheath. 

p. 109 Homoptera 

FF. Mouth-parts in normal position. Mandibles not bristle-like. 
G. Wings net-veined, with many veins and cross-veins. 
H. Tarsi consisting of less than five segments. 

I. Antennae inconspicuous, awl-shaped, short and slender. 

J. First and second pairs of wings of nearly the same length; 
tarsi three-jointed, p. 77 Odonata 

J J. Second pair of wings either small or wanting; tarsi four- 
jointed, p. 74 Ephemerida 

II. Antennas usually conspicuous, setiform, filiform, clavate, capitate, 

or pectinate. 
J. Tarsi two- or three-jointed. 

K. Second pair of wings the smaller, p. 83 Corrodentia 

KK. Second pair of wings broader, or at least the same size as 

the first pair. p. 81 Plecoptera 

JJ. Tarsi four-jointed; wings equal, p. 63 Isoptera 

HH. Tarsi consisting of five segments. 

I. Abdomen with setiform, many-jointed anal filaments. (Certain 

mayflies), p. 74 Ephemerida 

II. Abdomen without many-jointed anal filaments. 

J. Head prolonged into a trunk-like beak. p. 178 Mecoptera 

JJ. Head not prolonged into a beak. p. 66 Neuroptera 

GG. Wings with branching veins and comparatively few cross-veins, or 
veinless. 
H. Each of the veins of the wing extending along the middle of a 

brown line. p. 87 _ Embiidina 

HH. Wings not marked with brown lines. 


42 THE STUDY OF INSECTS 

I. Tarsi two- or three-jointed. 

J. Hind wings smaller than the fore wings. 

K. Cerci present; body less than three millimeters in length. 

p. 62 ZORAPTERA 

KK. Cerci absent; larger insects, p. 83 Corrodentia 

JJ. Posterior wings as large as or larger than the anterior ones. 
(Certain stoneflies). p. 81 Plecoptera 

II. Tarsi four- or five-jointed. 

J. Abdomen with setiform, many-jointed anal filaments (Certain 

mayflies), p. 74 Ephemerida 

JJ. Abdomen without many-jointed anal filaments. 

K. Prothorax horny. First wings larger than the second, naked 
or imperceptibly hairy. Second wings without or with 
few, unusually simple, veins. Jaws (mandibles) well de- 
veloped. Palpi small, p. 329 Hymenoptera 

KK. Prothorax membranous or, at the most, parchment-like. 
Second wings as large as or larger than the first, folded 
lengthwise, with many branching veins. First wings 
naked or thinly clothed with hair. Jaws (mandibles) in- 
conspicuous. Palpi long. Moth-like insects, p. 180 

Trichoptera 

AA. Wingless or with vestigial or rudimentary wings. 

B. Insects with a distinct head and jointed legs, and capable of locomotion. 
C. Aquatic insects. 

D. Mouth-parts fitted for piercing and sucking. 

E. Free-swimming nymphs, p. 94 Hemiptera 

EE. Larvae parasitic in sponges (Sisyridas). p. 66 Neuroptera 

DD. Mouth-parts fitted for chewing. 

E. Either somewhat caterpillar-like larvae that live in portable cases or 
campodeiform larvae that spin nets for catching their food. (Caddice- 

worms). p. 180 Trichoptera 

EE. Neither case-bearing nor net-spinning larvae. 

F. Naiads, that is, immature insects that resemble adults in having the 
thorax sharply differentiated from the abdomen, and, except in very 
young individuals, with rudimentary wings. 
G. Lower lip greatly elongated, jointed, capable of being thrust forward, 

and armed at its extremity with sharp hooks, p. 77 Odonata 

GG. Lower lip not capable of being thrust forward. 

H. Usually with filamentous tracheal gills on the ventral side of the 

thorax, p. 81 Plecoptera 

HH. Tracheal gills borne by the first seven abdominal segments. 

p. 74 Ephemerida 

FF. Larvae, that is, immature forms that do not resemble adults in the 
form of the body, and in which the developing wings are not visible 
externally. 
G. Several segments of the abdomen "furnished with prolegs. p. 183 

Lepidoptera 

GG. With only anal prolegs or with none. 

H. With paired lateral filaments on most or on all of the abdominal 

segments. (Sialidae). p. 66 Neuroptera 

See also Haliplidae and Gyrinidae. p. 127 Coleoptera 

HH. Without paired lateral filaments on the abdomen, p. 127 

Coleoptera 

CC Terrestrial insects. 
D. External parasites. 

E. Infesting the honey-bee. (Braula). p. 286 Diptera 

EE. Infesting birds or mammals. 

F. Body strongly compressed. (Fleas), p. 326 Siphonaptera 

FF. Body not strongly compressed. 

G. Mouth-parts formed for chewing. (Bird-lice), p. 85 . . . Mallophaga 
GG. Mouth-parts formed for piercing and sucking. 

H. Antennae inserted in pits, not visible from above. (Pupipara). 

p. 286 Diptera 

HH. Antennas exserted, visible from above. 


HEXAPODA 43 

I. Tarsi with a single claw which is opposed by a toothed projection 
of the tibia. (Lice), p. 92 Anoplura 

II. Tarsi two-clawed, p. 94 Hemiptera 

DD. Terrestrial insects not parasites. 

E. Mouth-parts apparently retracted within the cavity of the head so that 
only their apices are visible, being overgrown by folds of the genae. 
F. Abdomen consisting of ten or eleven segments. (Campodeida; and 

Japygidae). p. 45 Thysanura 

FF. Abdomen consisting of not more than six segments, p. 47 

COLLEMBOLA 

EE. Mouth-parts mandibulate, either fitted for chewing or with sickle- 
shaped mandibles formed for seizing prey. (See also EEE.) 
F. Larvae with abdominal prolegs. 

G. Prolegs armed at the extremity with numerous minute hooks. 

(Caterpillars), p. 183 Lepidoptera 

GG. Prolegs not armed with minute hooks. 

H. With a pair of ocelli, one on each side. (Larvae of saw-flies). 

p.3 2 9 Hymenoptera 

HH. With many ocelli on each side of the head. p. 178. .Mecoptera 
FF. Without abdominal prolegs. 

G. Body clothed with scales. (Machilidse and Lepismatidae) . p. 45 

Thysanura 

GG. Body not clothed with scales. 
H. Antennae long and distinct. 

I. Abdomen terminated by strong movable forceps, p. 125 

Dermaptera 

II. Abdomen not terminated by forceps. 

J. Abdomen strongly constricted at base. (Ants, etc.) p. 329 

Hymenoptera 

JJ. Abdomen not strongly constricted at base. 

K. Head with a long trunk-like beak. (Boreus). p. 178 

Mecoptera 

KK. Head not prolonged into a trunk. 

L. Insects of small size, more or less louse-like in form, with 
a very small prothorax, and without cerci. (Book-lice 

and Psocids). p. 83 Corrodentia 

LL. Insects of various forms, but not louse-like, prothorax not 
extremely small; cerci present. 
M. Hind legs fitted for jumping, hind femora enlarged. 
(Wingless locusts, grasshoppers, and crickets), p. 49 

Orthoptera 

MM. Hind femora not greatly enlarged, not fitted for 
jumping. 
N. Prothorax much longer than the mesothorax; front 
legs fitted for grasping prey. (Mantidas). p. 49 

. Orthoptera 

NN. Prothorax not greatly lengthened. 
O. Cerci present; antennae usually with more than 
fifteen joints, often many-jointed. 
P. Cerci with more than three joints. 

Q. Body flattened and oval. (Blattidae). p. 49 

Orthoptera 

QQ. Body elongate. 
R. Head very large. {Termopsis). p. 63 

ISOPTERA 

RR. Head of moderate size. p. 49 

Orthoptera 

PP. Cerci short, with one to three joints. 

Q. Body linear with very long linear legs. 

(Walking-sticks), p. 49 Orthoptera 

QQ. Body elongate or not, if elongate the legs 
are not linear. 
R. Body elongate; front tarsi with first joint 
swollen, p. 87 Embiidina 


44 THE STUDY OF INSECTS 

RR. Front tarsi not enlarged. 

S. Minute insects, less than J of an inch in 
length; antenna,' nine-jointed, p. 62 

ZoRAPTERA 

SS. Larger insects; antenna: usually more 
than nine-jointed. (White-ants), p. 63 

ISOPTERA 

00. Cerci absent; antennas usually with eleven 

joints, p. 127 COLEOPTERA 

HH. Antenna? short, not pronounced; larval forms. 

I. Body cylindrical, caterpillar-like. p. 178 Mecoptera 

II. Body not caterpillar-like. 

J. Mandibles sickle-shaped; each mandible with a furrow over 
which the maxilla of that side fits, the two forming an organ 
for piercing and sucking. (Ant-lions, aphislions, hemero- 

biids). p. 66 Neuroptera 

JJ. Mouth-parts not of the ant-lion type. 

K. Larva of Raphidia. p. 66 Neuroptera 

KK. Larvae of beetles, p. 127 Coleoptera 

EEE. Mouth-parts haustellate, fitted for sucking; mandibles not sickle- 
shaped. 
F. Body covered with a waxy powder or with tufts or plates of wax. 

(Mealy-bugs, Orthezia). p. 94 Hemiptera 

FF. Body more or less covered with minute scales, or with thick long 
hairs; proboscis if present coiled beneath the head. (Moths), p. 183 

Lepidoptera 

FFF. Body naked, or with isolated or bristle-like hairs. 

G. Prothorax not well developed, inconspicuous or invisible from 

above, p. 286 Diptera 

GG. Prothorax well developed. 

H. Last joint of tarsi bladder-like or hoof-like in form and usually 
without claws; mouth-parts forming a triangular un jointed 

beak. p. 89 Thysanoptera 

HH. Last joint of tarsi not bladder-like, and furnished with one 
or two claws; mouth-parts forming a slender, usually jointed 
beak. 

I. Beak arising from the front part of the head. p. 94. Hemiptera 

II. Beak arising from the back part of the head. p. 109. Homoptera 
BB. Either without a distinct head, or without jointed legs, or incapable of loco- 
motion. 

C. Forms that are legless but capable of locomotion; in some the head is dis- 
tinct, in others not. Here belong many larvas representing several of the 
orders, and the active pupas of mosquitoes and certain midges. It is im- 
practicable to separate them in this key. 
CC. Sedentary forms, incapable of locomotion. 

D. Small abnormal insects in which the body is either scale-like or gall-like in 

form, or grub-like clothed with wax. The waxy covering may be in the 

form of powder, or large tufts or plates, or a continuous layer, or of 

a thin scale, beneath which the insect lives. (Coccidae). p. 94 Hemiptera 

DD. Pupae, the inactive stage of insects with a complete metamorphosis; 

capable only of a wriggling motion, and incapable of feeding. 

E. Obtected pupae, pupas in which the legs and wings are glued to the 

surface of the body; either in a cocoon or naked, p. 183. . . .Lepidoptera 

EE. Coarctate pupas, pupae enclosed in the hardened larval skin. p. 286 

Diptera 

EEE. Exarate pupae, pupas that have the legs and wings free; either in a 
cocoon or naked. This type of pupa is characteristic of all of the orders 
in which the metamorphosis is complete except the Lepidoptera and 
Diptera. 


CHAPTER III 
ORDER THYSANURA* 


The Bristle-tails 

The members of this order are wingless insects still in a primitive con- 
dition. The mouth-parts are formed for chewing and the adults resemble the 
young in form for they do not have marked metamorphosis. The segments 
of the abdomen are of the usual number, eleven, and the last one usually 
bears two or three long, segmented, filiform appendages. 

The members of this order are known as bristle-tails, a name sug- 
gested by the presence, in most of them, of either two 
or three many-jointed filiform appendages at the caudal 
end of the body (Fig. 74) . The paired caudal appendages 
are the cerci; the median one, when three are present, 
is the median caudal filament, a prolongation of the 
eleventh abdominal segment. 

The bristle-tails are most often found under stones 
and other objects lying on the ground ; but some species 
live in houses. While most species prefer cool situations, 
there is one, the fire-brat, that frequents warm ones, 
about fire-places and in bakehouses. The antennas are 
long and many-segmented. There are less than twenty 
species known in this country. 

In one family the compound eyes are very perfect 
but in all others they are more or less degenerate or are 
lost entirely. 

The mouth-parts are formed for chewing but in 
many of the forms the jaws are apparently sunk in the 
head due to being overgrown by folds of the cheeks, or 
■ genas. In two families the jaws are not overgrown and 
the mouth-parts project in a normal manner. 
An interesting feature of some members of this order is the short, 
slender, two-segmented appendages found on the ventral side of the 
abdomen and known as styli. The styli are believed to be vestiges of 
legs persisting from many-legged ancestors probably centipede-like 
animals, the symphylids (See, An Introduction to Entomology, p. 23.) 

A common representative of this order is the fish-moth or silver-fish 
(Lepisma saccharina) as it is variously called. 

Often the careful housekeeper sees in the ironing-basket, or upon the 
book-shelf where she is dusting, a flash of light like a tiny thread of quick- 
silver, that usually vanishes as soon as seen. 

If she is experienced she knows that this streak of light is a little 
animal, half an inch long, whose body is clothed in shining scales like 
* Thysanura: thysanos (dOa-avos), a tassel; our a, (ovpa), the tail. 

45 


— Lepisma 


46 


THE STUDY OF INSECTS 


those of a fish. Hence she calls it a fish-moth. It is especially abundant 
in warm climates, and often docs damage to starched clothing, book- 
bindings, and sometimes loosens wall-paper 
by eating out the paste. Under a micro- 
scope the fish-moth shows beautiful mark- 
ings on the shining scales; and at the 
caudal end of the body are three long 
bristle-like appendages (Fig. 74), which sug- 
gest the common name bristle-tail applied 
to members of this suborder. 

Another common form is the fire-brat 
(Thenndbia domestica), which resembles 
the fish-moth in general appearance. It 
is remarkable for frequenting warm, even 
hot places, about ovens, ranges, and fire- 
places. 
(Afte G r' Lubb7ck.)^ . Figure 75 represents Japyx, a bristle- 
tail in which the caudal appendages are in 
the form of horny forceps; and Figure 76 represents the lower 
side of Machilis, another bristle-tail found under stones and m ackUis, showing 
bark. This is the form that has vestigial legs on the ab- appendages 
domen. 


Fig. 76. — 
Ventral aspect of 


Fig. 76a. — Campodea slaphylinus. 

An illustration of a small, delicate, whitish thysanuran, Campodea 
slaphylinus, which lives in damp places under stones or in rotten wood 
and leaves. Note that the thorax and abdomen differ from each other 
very little in form. This is true of many of these simple insects. (After 
Lubbock.) 


CHAPTER IV 
ORDER COLLEMBOLA* 


The Spring-tails 

The insects of this order are wingless insects still in a primitive condition. 
The mouth-parts are formed either for chewing or for sticking. The adults 
resemble the young in form for they do not have a marked metamorphosis. 
The segments of the abdomen are reduced to six in number. On the ventral 
side of the abdomen in many species is a springing organ. 

The spring-tails are minute insects, often of microscopic size and 
rarely more than 1/5 of an inch in length. Most of the species live on 
decaying matter. They are common under stones and decayed leaves 
and wood, in the chinks and crevices of bark, among moss, and on 
herbage in damp places. Sometimes they occur abundantly in winter 
on the surface of snow where they appear as minute black specks which 
spring away at our feet on either side. Some species collect in great 
numbers on the surface of standing pools of water. 

There is, on the underside of the fourth 
abdominal segment of most of these insects 
a fork-like appendage, the springing organ 
(Fig. 77), which, when the insect is at rest, is 
bent forward beneath the body and caught 
and held under tension by a catch on the third 
segment. When this organ is released it sud- 
denly springs-backward and throws the insect 
high in the air several feet away. This action 
is like a spring-board jump, only these tiny 
insects always carry their spring-boards with 
them, and thus have won the name of spring- 
tails. 

Typically, the mouth-parts of the spring- 
tails are chewing with the jaws overgrown by 
the cheeks until they are hardly visible. In a few forms the 
mandibles and maxillae have become modified into needle- 
like organs which are used for piercing and sucking. 

These insects possess a peculiar organ called the ventral 
tube, or collophore. It may be wart -like or tube-like in form and it is sit- 
uated on the underside of the first abdominal segment. It exudes a 
viscid fluid by means of which the insects are enabled to cling to the 
lower surface of an object. 

A common species of spring-tail is the snow-flea, Achorutes nivicola 
(Fig. 78), which occurs abundantly in winter on the surface of the snow. 

* Collembola: colla (n6\\a), glue; embolon (e^oXov), a bolt, bar; — from their 
collophores. 

47 


Fig. 77. — The 
"spring" of Papi- 
rius: via. manu- 
brium; d, left dens; 
mu, left mucro. 
(After Lubbock.) 


Fig. 78. — The 
snow-flea, Achorutes 
nivicola. (After Fol- 
som.) 


4 8 


THE STUDY OF INSECTS 


It sometimes proves a nuisance in sugar-bushes by getting into the 
sap. 

Another tiny one-, the garden-flea, Sminthurus hortensis, often be- 
comes a pest by feeding on young cabbages, 
turnips, cucumbers, and squashes. 

Through a microscope, certain spring-tails 
appear very absurd. They have long antennae 
and large dark eye-spots on the face, which, to- 
gether with the long hair that sticks forward 
on the head and thorax, give the creature a 
look of solemn fierceness (Fig. 79). Different 
Fir.. 79 .-Papiri*sfusc«s. (After species may be found at almost any time of the 
Lubbock.) year in damp places. 


Fig. 70a. — Tomocerus plumbe.ns, 


A side view of a spring-tail, Tomocerus plumbens, showing that cu- 
rious organ, the collophore, co; and the catch, c, which holds the spring, 
s, in place and under tension when the latter is drawn beneath the ab- 
domen. 


CHAPTER V 
ORDER ORTHOPTERA* 

Grasshoppers, Crickets, Cockroaches, and others 

The winged members of this order have two pairs of wings; the fore 
wings are more or less thickened, but have a distinct venation; the hind 
wings are folded in plaits like a fan when at rest; there are many forms in 
which the wings are vestigial or even wanting. The mouth-parts are formed 
for chewing. The metamorphosis is incomplete; the nymphs are terrestrial. 

The order Orthoptera includes some of the very common and best- 
known insects. The most familiar representatives are those named 
above. 

Although the song of the katydid and the chirp of crickets are most 
often associated with recollections of pleasant evenings spent in the 
country, we cannot forget that to members of this order are due some of 
the most terrible insect scourges man has known. The devastations 
caused by great swarms of migratory locusts are not only matters of 
historical record, but are too painfully known to many of our own 
generation in the western states. 

With the exception of a single family (Mantidce), the members of this 
order are, as a rule, injurious to vegetation; and many species are quite 
apt to multiply to such an extent that their destruction of vegetation 
becomes serious. 

In the Orthoptera the two pairs of wings differ in structure. The fore 
wings are parchment -like, forming covers for the more delicate hind 
wings. These wing-covers have received the special name tegmina; they 
are furnished with a fine network of veins, and overlap at the tip at 
least. There are many species in which the wings are rudimentary, 
even in the adult state. Such adults resemble nymphs; but in the case 
of the jumping Orthoptera, where this peculiarity most often occurs, 
nymphs can be distinguished by the fact that the rudimentary hind wings 
are outside of the fore wings, instead of beneath them, as in the adult 
state. 

There are six families of well-known insects in the order Orthoptera 
which can be separated by the following table. 

A. Hind femora fitted for jumping, i.e., very much stouter or very much longer, 
or both stouter and longer, than the middle femora; organs of flight of immature 
forms inverted; stridulating insects. (The Saltatorial Orthoptera.) 
B. Antennae long and setaceous, except in the mole-crickets and sand-crickets; 
tarsi three- or four- jointed; organs of hearing situated in the fore tibiae; oviposi- 
tor elongate, except in the mole-crickets and sand-crickets, with its parts 
compact. 
C. Tarsi four-jointed; ovipositor, when exserted, forming a strongly compressed, 

generally sword-shaped blade, p. 50 Tettigoniid^e 

* OrthSptera: orthos (6p06s), straight; pteron (irrepov), a wing. 

49 


So THE STUDY OF INSECTS 

CC. Tarsi usually three-jointed, except in the pigmy mole-crickets where they 

arc reduced; ovipositor, when exserted, forming a nearly cylindrical, straight, 

or occasionally upcurved needle, except in the Trigonidiinae. p. 53 . . . Gryllid^e 

BB. Antennae short; tarsi three-jointed; organs of hearing situated in the first 

abdominal segment; ovipositor short, with its parts separate, p. 56 

_■ Locustid^: 

A.\. Hind femora closely resembling those of the other legs, and scarcely if at all 

stouter or longer than the other femora, i.e., not fitted for jumping; organs of 

flight in a normal position when immature; stridulating organs not developed. 

B. Body elongate; head free; pronotum elongate; legs slender, rounded; cerci 

jointed or without joints; walking insects. 

C. Front legs simple; cerci without joints, p. 58 Phasmid/E 

CC. Front legs fitted for grasping; cerci jointed, p. 59 Mantid/E 

BB. Body oval, depressed; head wholly or almost wholly withdrawn beneath the 
pronotum; pronotum shield-like, transverse; legs compressed; cerci jointed; 
rapidly running insects, p. 60 Blattid/E 

Family Tettigoniid^; 

The Long-homed Grasshoppers 

This family has usually been given the name Locustidag, but this 
name should be used for the family of short-horned grasshoppers or 
locusts. The members of this family are among the most attractive in 
appearance of the Orthoptera. In many of them the wings are graceful 
in form and delicate in color, and the antennae are exceedingly long and 
slender, looking more like ornaments than like organs of practical use. 
The tarsi are four-segmented and the ovipositor is sword-shaped. 

These beautiful creatures are much less frequently seen than are the 
crickets and locusts because of their protective green color, which renders 
them inconspicuous in their haunts among foliage or on the blades of 
grass. Their presence is most often indicated by the chirping of the 
males. 

Any one that is in the habit of lying in the tall grass of meadows or 
pastures and watching the insects that can be seen there is sure to be 

familiar with certain green grass- 
hoppers, which attract attention by 
the extreme delicacy and great 
length of their antennas. The 
antennas are much more slender 
than with the short -horned grass- 
hoppers or locusts, and much longer, 
exceeding the body in length. The 
tarsi are four-jointed. The ear- 
like organs, when present, are situ- 
ated near the base of the fore tibiae 
(Fig. 80), and the ovipositor is 
sword-shaped. 

In those species of this family 
„ „ _ r , ,. , , in which the wings are well de- 

ric. 80. — Leg of katydid, showing car-like organ. 1 -. c -, ,1 1 ■ • j„ j 

vol oped we find the males provided 
with an elaborate musical apparatus by means of which they call their 
mates. This consists of a peculiar arrangement of the veins and cells of a 
portion of each wing-cover near its base. This arrangement differs in the 
different species ; but in each it is such that by rubbing the wing-covers 


ORTHOPTERA 


5i 


Fig. 81. — Wing 
cover of male mead 
ow grasshopper. 


82. — Wing- 
of female 
meadow grasshopper. 


together they are made to vibrate, and thus produce the sound. Figure 
81 represents a wing-cover of the male of a common meadow grasshop- 
per, and Figure 82 that of a female of the 
same species. 

In order to facilitate the study of this 
family the more common representatives can 
be arranged in four groups; the katydids, 
the meadow grasshoppers, the cricket-like 
grasshoppers, and the shield-backed grass- 
hoppers. 


THE KATYDIDS 


The chances are that he who lies awake 
of a midsummer night must listen whether 
he wishes to do so or not, to an oft-repeated, FlG 
rasping song that says, "Katy did, Katy cover 
did ; she did, she didn't," over and over again 
There is no use of wondering what Katy did or didn't do, for no mortal 

will ever know. If, when the dawn comes, 
the listener has eyes sharp enough to discern 
one of these singers among the leaves of some 
neighboring tree, never a note of explana- 
tion will he get. The beautiful, finely- 
veined wings folded close over the body 
keep the secret hidden, and the long an- 
tennae, looking like threads of living silk, 
will wave airily above the droll, green eyes 
as much as to say, "Wouldn't you like to 
know?" The katydids live among the 
branches of trees and the song made by 
the male is heard at night and occasion- 
ally on dark cloudy days. The true 
northern katydid, Pterophylla camellifdlia, 
is the species commonly known as the 
"Katydid" owing to its characteristic 
strident call. It is found throughout the 
United States east of the Rocky Moun- 
tains; but in the North it lives in col- 
onies which occupy rather restricted areas 

(Fig- 83). 

There are several species of false katy- 
dids with broad leaf-like wings that live 
in trees and look much like the real katy- 
did. One of these is known as the an- 
gular-winged katydid, Microcentrum 
rhomb if olium. It deposits its large ellip- 
tical eggs in rows along the edge of a leaf or 
on a small branch (Fig. 84). 
There is another species of angular-winged katydid, Microcentrum 
retinerve, which is somewhat smaller than the preceding but closely re- 
sembles it in form and appearance. 


Fig. 83. — Pterophylla 
(After Harris.) 


camellifolia. 


52 


THE STUDY OF INSECTS 


Fig. 84. — The angular-winged katydid and its eggs. 


THE MEADOW GRASSHOPPERS 


From the middle of the summer to the autumn there can be found 
upon the grass in our meadows and moist pastures many light-green long- 


Fig. 85. — Conocephalus. 


Fig. 86 — Ceuthophilus. 


horned grasshoppers of various sizes; these, on account of the situations 
in which they are usually found, are termed the meadow grasshoppers. 
They are of medium size and are the most common members of this 
family (Fig. 85). Associated with the meadow grasshoppers and living in 
the same situations, are often found larger, longer-winged grasshoppers 
with pointed heads, called the cone-headed grasshoppers. 


THE CRICKET-LIKE GRASSHOPPERS 


These are the long-horned grasshoppers that bear some resemblance 
to the true crickets (Fig. 86). They have a short, thick body and re- 
markably stout hind femora, like a cricket, but are entirely destitute of 
tegmina and wings. The more common species are either of a pale 


ORTHOPTERA 53 

brown or a dirty white color and more or less mottled with either lighter or 
darker shades. Most of them fall in the genus Ceuthophilus (Fig. 86). 

These insects live in dark and moist places, under stones and rubbish, 
especially in woods, in cellars, in the walls of wells, and in caves. They 
are commonly called cave-crickets and some, because of the high arched 
back, camel-crickets. 

THE SHIELD-BACKED GRASSHOPPERS 

These are mostly wingless or nearly wingless, dull-colored insects 
which bear some resemblance to crickets. They present, however, a 
queer appearance, due to the pronotum extending backward over the 
rest of the thorax, like a sun-bonnet worn over the shoulders with the 
back side forward. These insects live in grassy fields or open woods. 
Most of them occur west of the Mississippi but a few of the genus Atldn- 


Fig. 87. — Atlanlicus. Fig. 88. — Stenopelmatus. 

ticus occur in the East (Fig. 87). Some of the shield-backed grasshop- 
pers of the genus Anabrus, popularly known as the western cricket, invade 
cultivated fields at times in the western states and destroy the crops. 

The sand-crickets of the Pacific Coast are not widely unrelated to the 
shield-backed grasshoppers. They are clumsy creatures with big heads 
that live under stones in loose soil. They belong to the genus, Sten- 
opelmatus (Fig. 88). 

Family Gryllid^e 
The Crickets 

In the more typical crickets the hind legs are fitted for leaping and the 
antennae are long and slender. The tegmina lie flat on the back and are 
bent down abruptly at the sides of the body like a box-cover. The 
ovipositor is spear-shaped and wings are absent in some species. 

There are crickets, however, which have short antennas, some in which 
the ovipositor is sword-shaped and a few without an ovipositor. 

With most species of crickets the males differ greatly in appearance 
from the females. The males have musical organs which are even more 
elaborate than those of the katydids and meadow grasshoppers. Here all 
that part of each wing-cover that lies on the back is occupied by them. 
This gives the males a very different appearance from the females, the 
wing-covers of that sex being veined simply. 

During the latter part of summer and in the autumn the air is filled 
with the chirping of crickets. It is an interesting thing to watch one of 


54 


THE STUDY OF INSECTS 


Mm 


these fiddlers calling his mate. By moving quietly in the direction from 
which the sound comes, and stopping whenever the insect stops chirping, 
but moving on again when he renews his song, one can get near enough 
to see how he does it. This can be done even in the 
night with the aid of a lantern, as the crickets do not 
seem to mind lights. 

Figure 89 represents the musical apparatus of a 
cricket. From this it will be seen that the large 
veins divide the wing-covers into disk-like membra- 
nous spaces. If the principal vein which extends 
diagonally across the base of the wing-cover be ex- 
amined with a microscope, it will be seen to be fur- 
nished with ridges like those of a file (Fig. 89, C). On 
the inner margin of the wing-cover, a short distance 
toward the base from the end of the principal vein, 
there is a hardened portion which may be called the 
scraper. This is shown enlarged at s in the figure. 
Each wing-cover is therefore provided with a file and 
a scraper. When the cricket wishes to make his call, 
he elevates his wing-covers at an angle of about 
forty-five degrees with the body ; then holding them 
in such a position that the scraper of one rests upon 
the file of the other, he moves the 
wing-covers back and forth sidewise 
so that the file and the scraper rasp 
upon each other. This throws the 
wing-covers into vibration, and pro- 
duces the call. 

The crickets do not constitute a 

Fig. 89. — Fore wing , -j ui 

of Gryiius; a, as seen large group yet there is considerable 
S^^SH^t diversity of form among them. The 
down on the side of the m ore common species may be placed 

abdomen is not shown; . , ,. L ... .. J ., 

s, scraper; /,/, tympana, in three rather distinct groups; the 
beio'wT t SET/fiE tree-crickets, the field-crickets, and the 

C, file greatly enlarged. mole-cricketS. „££ ^~ ^^ 


THE TREE-CRICKETS 

The common name of this group was suggested by the fact that these 
crickets are very apt to inhabit trees; but they occur also on shrubs, or 
even on high herbs and tall grass. They are delicate insects, many of 
which are of a light green color. Most of them belong to the genus 
(Ecanthus and the one that often attracts attention is the snowy tree- 
cricket, 0. mveus (Fig. 90). Although usually unseen the males arc evi- 
dent in late summer and in the autumn by their songs. Their song is 
begun early in the evening and is continued throughout the night; it 
consists of a monotonous scries of high-pitched trills rhythmically re- 
peated indefinitely. It is a remarkable fact that all of these crickets that 
are chirping in any locality chirp in unison. Except where the true katy- 
did is heard, this is the most conspicuous insect song heard in the night 
in the regions where this species occurs. 


ORTHOPTERA 


55 


Another species, 0. nigricornis, attracts attention because the female 
lays her eggs in a row in the stems of plants, especially in the canes of 
raspberries (Fig. 91). 

The field-crickets 

These are the common 
brown to almost black crickets 
with which we are probably 
most familiar. 

They abound everywhere, 
in pastures, meadows, and 
gardens; and certain species 
enter our dwellings . They lurk 
under stones or other objects 
on the ground or burrow into 


Fig. 92. — Gryllus 


Fig. 93. — Gryllo- 
lalpa hexadactyla. 


the earth. They are chiefly solitary, nocturnal in- 
sects; yet many can be seen in the fields in the 
daytime. They usually feed upon plants but are 
sometimes predacious. With most species the eggs 
are laid in the autumn, usually in the ground, and 
are hatched in the following summer. The greater 
number of the old crickets die on the approach of winter; but a few 
survive the cold season. In many of the species there are both short- 
winged and long-winged forms. In Figure 92 is shown a common short- 
winged form. The house cricket of Europe, Gryllus domesticus, is now 
present in the northeastern United States. 


Fig. 91. — Stem of black 
raspberry with the eggs of 
(Ecanlhus nigricornis: c, d, egg 
enlarged. (From Riley.) 


The mole-crickets 

These are called mole-crickets because they burrow in the ground like 
moles. The form of the body is suited to this mode of life. The front 
tibiae, especially, are fitted for digging; they are greatly broadened, and 
shaped somewhat like hands, or the feet of a mole (Fig. 93). 

The mole-crickets are not common insects in this country; but oc- 
casionally they are found in great numbers in a limited locality. They 
make burrows in moist places from six to eight inches below the surface 
of the ground, and feed upon the tender roots of various plants, and also 
on other insects. The eggs are deposited in a neatly constructed sub- 
terranean chamber, about the size of a hen's egg. 

In this country, at least, mole-crickets are nocturnal in habits, coming 
forth at night to feed and remaining hidden in their burrows during the 
day. 


56 


THE STUDY OF INSECTS 
Family Locustid/£* 


The Locusts or Short-honied Grasshoppers 

The family Locustida? includes the locusts or short-horned grass- 
hoppers. These are common and well-known insects. The antennas are 
much shorter than the body, and consist of not more than twenty-five 
segments. The ovipositor of the female is short and composed of separate 
plates; and the basal segment of the abdomen is furnished on each side 
with a tympanum, the external parts of the organs of hearing (Fig. 94). 

It is to these insects that the term locust is properly applied; for the 
locusts of which we read in the Bible, and in other books published in 
the older countries, are members of this family. Unfortunately, in the 
United States the term locust has been applied to the Periodical Cicada, 
a member of the order Homoptera, described later. 

Locusts lay their eggs in oval masses and cover them with a tough 


Fig. 94. — Side view of Locust with wings removed to show 
ear. See the arrow. 


Fig. 95. 

brum. 


Mclanoplus femur-ru- 


substance. Some species lay their eggs in the ground. The female makes 
a hole in the ground with her ovipositor, which is a good digging-tool. 
Some species even make holes in fence-rails, logs, and stumps; then, 
after the eggs are laid, the hole is covered up with a plug of gummy 
materials. There is but one generation a year, and in most cases the 
winter is passed in the egg-state. This family is of great economic im- 
portance, as the members of it usually appear in great numbers in every 
region where plants grow, and often do much damage. 

The males of many locusts are able to produce sounds. This is done 
in two ways: first, certain species rub the inner surface of the hind 
femora, upon which there is a row of minute spines, against the outer 
surface of the wing-covers. In this case each wing-cover serves as a 
fiddle, and each hindleg as a fiddle-bow. Second, other species rub to- 
gether the upper surface of the front edge of the hind-wings and the 
under surface of the wing-covers. This is done while the locust is flying 
and the result is a crackling sound. 

There are very many species of locusts in the United States. We 
have space to refer to only a few here. 

The most familiar member of the family is the red-legged locust, 
Mclanoplus femur-ruhrum (Fig. 95). It is more abundant than any 
other species throughout the United States, except in the high dry lands 
of the central part of the continent where the Rocky Mountain locust, 
Melanoplus sprctus, has its breeding grounds. 

The Rocky Mountain locust is only about one to one and a quarter 

* This family is termed the Acrididas by some writers, other writers use the fam- 
ily name Acridiidaj. 


ORTHOPTERA 


57 


inches long and resembles closely the red-legged locust but has somewhat 
longer wings. In past years when the food of this locust has become 
scarce in its high dry home, it has migrated to the lower and more fertile 
regions of Kansas, Iowa and Nebraska where it has devastated the crops 
over large areas. 

It will be remembered that at one time it almost produced a famine 
in Kansas and the neighboring states. Fortunately the young of this 
insect hatched in the low regions are not healthy, and die before reaching 
maturity. Consequently the plagues caused by the emigration of this 
insect are of short duration. There are several other species of Melano- 
plus common in this country, but they can be distinguished only by very 
careful study. One, the "big yellow locust", Meldnoplus dijjferentialis, is 
about if inches long, yellowish-brown in color and often so abundant 
in the middle West that it injures fields of grass and grain very seriously. 
The Carolina locust, Dissostclra Carolina, is common throughout the 
United States and Canada, and at the North is our largest species. It 
lives in roads and on bare places, and its color matches the soil on which 
it lives. It is usually pale yellowish or reddish-brown or slate color, with 
small dusky spots. The hind wings are 
black, with a broad yellow edge. It meas- 
ures from one inch and a half to nearly 
two inches in length. 

The clouded locust, Encoptolophus sor- 
didus (Fig. 96), is very common in the 
Eastern United States during the au- 
tumn. It abounds in meadows and pastures, and attracts attention by the 
crackling sound made by the males during flight. Its color is dirty brown, 
mottled with darker spots. 

The American locust, Schistocerca americana, is a fine species nearly 

3 inches long. It 
is found in the 
southern states 
and as far north 
as Connecticut 
and Iowa (Fig. 
97). The pellucid 
locust, Cam- 
nula pelliicida, 
scarcely an inch 
in length, has 
clear pellucid 
south to Arizona. 


Fig. q6. — Encoptolophus sordidus. 


It 


is a large, clumsy species 
it is confined to the cen- 


Fig. 07. — Schistocerca americana. (From Riley.) 

hind wings and occurs in the northern United States 
is often injurious to crops. 
The lubber grasshopper, Brachystola magna, 
in which the wings are vestigial 
tral portion of North America. 

The pigmy locusts. — There is a group of small locusts 
of which Acrydium (Fig. 98) is an example, which is no- 
table for the shape of the pronotum. This projects back- 
ward like a little roof over the wings, and often extends beyond the end of 
the abdomen. With these insects the wing-covers are reduced to small 
rough scales, the wings being protected by the large pronotum. These in- 


Fig. oS. — Acrydiur, 


58 


THE STUDY OF INSECTS 


sects arc commonly found in low, wet places, and on the borders i if streams. 
Their colors are usually dark, and are often protective, closely resembling 
that of the soil upon which they occur. These locusts are very active, 
jumping great distances. 


Family Phasmid^e 
The Walking-sticks and the Leaf -in sects 

The Phasmidae are of especial interest on account of the remarkable 

mimetic forms of the different species. In those species that are found in 

the United States, except one in Florida, the body 
is linear (Fig. 99), wingless, and furnished with 
long legs and antennas. This peculiar form has 
suggested the name walking-sticks which is com- 
monly applied to these insects. 

These insects are strictly herbivorous; they 
are slow in their motions, and often remain quiet 
for a long time in one place. They evidently de- 
pend on their mimetic form for protection. In 
addition to this some species have the power of 
ejecting a stinking fluid, which is said to be very 
acrid; this fluid comes from glands placed in the 
thorax. 

The eggs are scattered on the ground beneath 
the plants upon which the insects feed, the female, 
unlike most Orthoptera, making no provision for 
their safety. In our 
common northern 
species the eggs are 
dropped late in the 
summer and do not 
hatch till the follow- 
ing spring, or even 
till the second spring 
in some cases. 

Our common 
northern walking- 
stick is Diaphero- 
mera femorata (Fig. 
99). The range of 
this species extends 
quite common insect, 

and on several occasions has appeared in such 

great numbers as to be seriously destructive to 

the foliage of forest trees ; but these outbreaks 

have been temporary. 

Among the more striking in appearance of 

the walking-sticks found in the South are Mega- 

phasma dcntricus, our largest species, measuring from 5 to 6 inches in length, 

and Anisomorpha buprestoides, a yellowish brown species, about half as long 

as the preceding. 


Fig. gg. — A Walking-stick. 

into Canada. It is a 


Fig. 100. — Phyllium scythe. 
Sharp, after Westwood.) 


(From 


ORTHOPTERA 


59 


While our species are all wingless, except Aplopus mayeri, found in 
southern Florida, many exotic species are furnished with wings; and with 
some of these the wings resemble leaves. Among the more remarkable 
of the leaf-insects, as they are known, are those of the genus Phyllium 
(Fig. ioo), the members of which occur in the tropical regions of the 
Old World. 

Family Mantid^e 

The Praying Mantes or Soothsayers 

Certainly they are pious-looking fellows, with their front 
legs clasped together in front of their meek, alert faces, and 
it is no wonder that they are called praying mantes. But 
the only prayer that could ever enter the mind of a mantis 
would be that some unwary insect might come near enough 
for him to grab it with his hypocritical claws, and so get a 
meal. 

The praying mantes are easily recognized by the unusual 
form of the pro thorax and of the first pair of legs (Fig. 102). 
The prothorax is elongated and the front legs are large and 
fitted for seizing prey. The coxa? of the front legs are very 
long, and the femora and tibiae of these legs are armed with 
spines ; the tibia of each leg can be folded back against the 
femur so that the spines of the two will securely hold any 
insect seized by the praying mantis. 

With some species the wings resemble leaves of plants in 
form and coloring. 

All of the species are carnivorous, feeding on other in- 
sects. They do not pursue their prey but wait patiently 
with the front legs raised like uplifted hands in prayer, until 
it comes within reach, when they seize it. 

The eggs of the Mantidas are encased in chambered 
ooth ecas, which are usually fastened to the stems or twigs 
of plants (Fig. 101). 

Most of the members of this family are tropical insects; a few species, 
probably less than twenty, live in the southern half of the United States; 
and one of our native species, Stagmomantis Carolina (Fig. 102), is found 
as far north as Maryland and southern Indiana. 


Fig. ioi. — Egg- 
cases of Stagmoman- 
tis Carolina. (From 
Riley.) 


6o 


THE STUDY OF INSECTS 


Recently two exotic species have been introduced into the Northern 
States, probably by the importation of oothecae on nursery stock, and 
have become established here. These are the Mantis religiosa of Europe, 
which was first observed in this country near Rochester, N. Y., in 1899, 
and Paratcnodcra sinensis of China and Japan, which was first observed 
here at Philadelphia about 1895. 

Family Blattid^; 
The Cockroaches 

The cockroaches are well-known insects with oval depressed bodies, 
long slender antennae and legs fitted for running. The head is bent 
downward and the mouth-parts project backwards between the first pair 
of legs. 

After every one is in bed at night and all is quiet in the kitchen where 
there are water-pipes, often a throng of these small creatures come forth 
from hiding-places and, like brownies, take possession of everything. 
They race around everywhere, trying to find something to eat, almost 
anything that comes in reach of their greedy jaws. They eat book-bind- 
ings and bedbugs, if they find them, with equal alacrity. 


Fig. 103. — The Croton-bug; a, first instar; b, second instar; c, third instar; 
d, fourth instar: e, adult; /, adult female with egg-case; 4', egg-case, enlarged; 
h, adult with wings spread. All natural size except g. (From Howard and 
Marlatt.) 

Not only are these insects very destructive to our possessions, but 
owing to their fetid odor merely the sight of them awakens disgust. 

The eggs of cockroaches are enclosed in purse-like capsules (Fig. 103, g). 
These capsules, or oothecae, vary in form in different genera, but are more 
or less bean-shaped. Within, the ootheca is divided into two parallel 
spaces, in each of which there is a row of separate chambers, each cham- 
ber enclosing an egg. The female often carries an ootheca protruding 
from the end of the abdomen for several days. It has been found that 
a single female may produce several oothecae. Probably the most effec- 
tive means of ridding premises of cockroaches is by dusting the places 
they frequent with commercial sodium fluoride. 

In the Northern States our native species are usually found in the 
fields or forests under sticks, stones, or other rubbish. But certain im- 
ported species become pests in dwellings. In the warmer parts of the 
country, however, native and foreign species alike swarm in buildings of 
all kinds, and are very common out of doors. 


ORTHOPTERA 


61 


The croton-bug, Blattella germanica, is the most common house cock- 
roach in the North. It came from Europe and was first found about 
water-pipes in New York City connected with the Croton aqueduct. 
It is pale brown and only a little over \ an inch long (Fig. 103). 


Fig. 104. — The American cockroach. 


The American cockroach, Periplancta americdna (Fig. 104), is a native 
of tropical or subtropical America that has become distributed both in 
tropical and mild climates over the entire world. This is a large species 
measuring from 1 to if inches in length. 

The oriental cockroach, Blatta orientalis, is supposed to have come to 
us from Asia. It measures from f of an inch to nearly an inch in 
length and is blackish-brown in color. The wings of the female are very 
short. 


CHAPTER VI 


ORDER ZORAPTERA 


So little is known of this order which was established in 1913, that it 
is impossible at this time to define with any certainty, the characters of 
the group. But a single genus, Zorotypus, is known, and at this time, 
only about half a dozen species have been discovered. These have been 
found as follows: one each in Africa, Ceylon, Java, and Costa Rica and 
two in Florida. One of the species from Florida has also been found in 
Texas. In addition, a colony of one species has been discovered in north- 
ern Virginia. 

The known species are all minute, the largest measuring only -fa 
of an inch in length. The Florida species contain both winged and wing- 
less forms, the former being females although there are also wingless 
females. 


Fig. 105. — Zorotypus hubbardi; /, winged adult female; 5, antenna of a wing- 
less individual. (From An Introduction to Entomology.) 

The wingless adults resemble small termites. They have strong man- 
dibles but are blind. The legs arc fitted for running and the antennas are 
nine-segmented. The winged females have compound eyes and two pairs 
of wings (Fig. 105). 

These insects are social and live in colonies of various sizes under the 
bark of logs and stumps and frequently near the galleries of termites. It 
was thought, at first, that they might live as inquilines in the nests of 
termites; but recent observations do not support this view. 

* Zoraptera: zoros (£vp6s), pure; apterous (din-epos), without wings. 

62 


CHAPTER VII 
ORDER ISOPTERA* 

The Termites or White-ants 

The members of this order are social insects, living in colonies like ants. 
Each species consists of several distinct castes, the number of which differs 
in different species. Each caste includes both male and female individuals. 
In most species there are four castes as follows: first, the first reproductive 
caste, in which the wings become fully developed and are used for a swarming 
flight and then shed; second, the second reproductive caste, in which the 
wing-buds remain short; the individuals are sexually mature but retain the 
nymphal form; third, the worker caste; and fourth, the soldier caste. Ex- 
cept in a single Australian genus, the two pairs of wings are similar in 
form and in the more general features of their venation; they are long and 
narrow, and are laid flat on the back when not in use. The abdomen is 
broadly joined to the thorax; the mouth-parts are formed for chewing; the 
metamorphosis is incomplete. 

The termites or white-ants are chiefly tropical insects; but some 
species live in the temperate zones. These insects can be easily recog- 
nized by the fact that they live in ant-like colonies, by the pale color of 
the greater number of individuals of which a colony is composed, and by 
the form of the abdomen, which is broadly joined to the thorax instead 
of being pedunculate as in ants. 

The termites are commonly called white-ants on account of their 
color and of a resemblance in form and habits to the true ants. In 
structure the termites and ants are widely separated. In habits there is 
little more in common than that both are social. 

The cuticula of termites is delicate even in adults; the mature winged 
forms can withstand exposure to dry air for a limited period, as is neces- 
sary during their swarming flight ; but other members of a colony quickly 
become shriveled and die if exposed. It is for this reason that they build 
tubes constructed of earth and excrement for passage-ways, and only 
rarely appear in the open, and then merely for a brief period. 

The mouth-parts resemble those of the grasshoppers; but in the case 
of the soldier caste the mandibles are very large. The members of the 
winged sexual caste have compound eyes and a pair of ocelli. The 
workers and soldiers of most termites are blind but in case of the march- 
ing termite of Africa both the workers and soldiers possess eyes. 

The wings are long and narrow and when folded on the back of the 
insect extend far beyond the end of the abdomen. The wings of the 
sexual forms are shed after their flight. The shedding of the wings is 
facilitated by the presence in each wing near its base of a curved trans- 
verse suture, the humeral suture. 

* Isfiptera: isos (tow), equal; pier on (irrcpov), a wing. 
63 


64 


THE STUDY OF INSECTS 


With the termites the number of castes is greater than with the social 
bees, social wasps, and ants; and each caste includes both male and 
female individuals. The termites differ also from other social insects in 
that there arc at least two and sometimes three castes whose function 
is reproduction. The following castes have been found among these 
insects. 

The first reproductive caste. —At a certain season of the year, late 
spring or early summer for our most common species in the eastern 
United States, there can be found in the nests individuals with fully 
developed wings. These are sexually perfect males and females and 
constitute what is known as the first reproductive caste. In these the 
cutieula is black or dark chestnut in color and the eyes arc functional. 
A little later, these winged individuals leave the nest in a body; some- 
times clouds of them appear. After flying a greater or less distance they 
alight on the ground, and then shed their wings. 

At this time the males seek the females and they become associated 
in pairs. Each of the more fortunate couples that have escaped their 
enemies, find a suitable place for the beginning of a nest and become 
the founders of a new colony. Such a pair are commonly known as the 
king and the queen of the colony; they are also known as the primary 
royal pair. 

After the nest has been begun, the abdomen of the female becomes 
greatly enlarged, as a result of the growth of the reproductive organs and 
their products ; this is greater in certain exotic species than 
it is in those found in this country. Figure 106 represents 
in natural size the queen of a species found in India. This 
queen is comparatively small. In some species the queens 
become 6 to 8 inches in length ; such queens are incapable 
of locomotion and rest in a cell with nothing to do but lay 
eggs. In our native species of termites the queens do not 
become so large and they do not lose their power of move- 
ment. 

The second reproductive caste. — There are 
frequently found in the nests of termites in- 
dividuals which arc sexually mature but 
which retain the nymphal form of the body, 
having short wing-buds which do not develop 
further. These individuals constitute the 
second reproductive caste, which is represented 
by both males and females. The members of 
this caste are pale in color; their compound 
eyes are only slightly pigmented; and they FlG . I07 ._ Wo rker 
TeTme's never leave the nest unless by subterranean of Reticuiitermes 
tunnels. If a primary king or queen dies, its 
place is taken by individuals of the second reproductive caste. For this 
reason, the members of this caste are commonly known as substitute kings 
and queens or as complemental kings and queens. 

The workers. — If a termite nest be opened at any season of the year 
there will be found a large number of wingless individuals of a dirty 
white color, usuallv blind, and of the form represented by Figure 107. 
These are named the workers, for upon them devolve nearly all of the 
labors of the colony. A study of the internal anatomy of workers has 


Fie. 106. — ^)ueen 
white-ant 
gilvus. 


ISOPTERA 65 

shown that both sexes are represented in this caste. The worker caste is 
not always present. 

The soldiers. — ■ Associated with the workers, and resembling them in 
color and in being wingless, there occur numerous representatives of 
another caste, which can be recognized by the enormous size 
of their heads and mandibles (Fig. 108); these are the sol- 
diers. They are so named because it is believed that their 
chief function is the protection of the colony; but they do 
not seem to be very effective in this. Among the soldiers, 
as among the workers, both sexes arc represented. 

The nest-building habits of these insects are remarkable. 
In the tropics certain species build mound nests ten or 
twelve feet or more in height. Other species build large 
globular masses upon the trunks or branches of trees or upon 
other objects. Owing to the delicacy of their cuticula and 
the consequent danger of becoming shriveled if exposed, the FlG Io8 _ So] . 
termites build covered ways from their nests to such places <jier of Retkuiitermes 
as they wish to visit, if they are in exposed situations. These 
exposed nests are composed chiefly of the excreted undigested wood upon 
which the insects have fed. This is molded into the desired form and on 
drying it becomes solid. 

The termites that live in the United States do not build exposed 
nests; and, as the queens do not lose the power of movement, there is 
no permanent royal cell, centrally located. Some of our species mine in 
the earth, their nests being made under stones or other objects lying 
on the ground; some burrow only in wood; and others that burrow in 
the ground extend their nests into wood. 

In the warmer parts of this country and in the tropics termites are a 
great pest for they destroy buildings by mining into the foundation 
beams and into the timbers of the framework. Certain methods have 
been devised for the construction of buildings in warm countries for the 
purpose of making them termite-proof. 

Termites also destroy furniture and books, especially when the latter 
are stored in basements. In - infesting anything composed of wood, they 
eat out the interior, leaving a thin film on the outside. Thus a table may 
appear to be sound, but crumble tc pieces beneath a slight weight, en- 
trance having been made through the floor of the house and the legs of 
the table. 

While termites infest chiefly dead wood, there are many records of 
their infesting living plants, especially young orange and pecan trees in 
the South. 

The common species of termite in the northeastern United States is 
Reticulitermes flavipes. It often infests the wooden benches in greenhouses 
and in some localities undermines buildings by eating out the inside of 
the foundation timbers and then burrowing into the framework. 


CHAPTER VIII 
ORDER NEUROPTERA* 


The Horned Corydalus, the Lacewing-flies, the Ant-lions and others 

The members of this order have four wings; these are membranous and 
are usually furnished with many veins and cross-veins. In most members 
of the order, the wings have been specialized by the addition in the preanal 
area of many supernumerary veins of the accessory type. The mouth-parts 
are formed for chewing. The tarsi are five-jointed. The cerci are absent. 
The metamorphosis is complete. 

The order Neuroptera as now restricted differs greatly in extent from 
the Neuroptera of the early entomologists. Formerly there were included 
in this order many insects that are no longer believed to be closely re- 
lated. 

The wings of the Neuroptera are membranous 
and are usually furnished with many wing-veins. 
The two pairs of wings are similar in texture and 
usually in outline; in some the fore wings are 
slightly larger than the hind wings, in others the 
two pairs of wings are of the same size. The anal 
area is small in both fore and hind wings; it is 
rarely folded (Sialidae), and then only slightly so. 
The mouth-parts are formed for chewing. In 
several families the larva? suck the blood of their 
prey by means of their peculiarly modified man- 
dibles and maxilla?. The mouth-parts of the larva 
of an ant-lion will serve to illustrate this type of 
mouth-parts (Fig. 109). 

In this insect the mandibles {md) are very 
long, curved at the distal end, fitted for grasping 
and piercing the body of the prey, and armed with 
strong spines and setae. On the ventral aspect of 
each mandible there is a furrow extending the 
entire length of the mandible ; and over this fur- 
row the long and slender maxilla (mx) fits. On 
the dorsal aspect of the maxilla there is also a 
furrow. These two furrows form a tube which 
extends from the tip of the combined mandible 
and maxilla to the base of this organ where it 
communicates with the mouth cavity. Through this tube the blood of the 
prey is conveyed to the mouth. 

The metamorphosis is complete. The larvae that are known are pre- 
dacious or parasitic; a few of them are aquatic, Sialidae, Sisyridae, and 
* NeurOptera: neuron (vtvpov), a nerve; pteron (Trrtpov), a wing. 

66 


ioq. — Ventral side 
mouth-parts of an ant-lion: md, 
mandible; mx, maxilla. Much en- 
larged. 


NEUROPTERA 67 

certain exotic forms, but more of them are terrestrial; some when full- 
grown enter the ground and make earthen cells in which they transform, 
but most of them spin cocoons. The silk of which these cocoons are 
made, in the case of those in which the silk-organs have been described, 
is secreted by modified Malpighian vessels and is spun from the anus. 

The known Neuroptera of the world represent twenty families. 
Thirteen of these families are represented in North America; these can 
be separated by the following table. 

TABLE OF THE FAMILIES OF NORTH AMERICAN NEUROPTERA 

A. Prothorax as long as or longer than the mesothorax and metathorax combined. 

B. Fore legs greatly enlarged and fitted for grasping, p. 71 Mantispuxe 

BB. Fore legs not enlarged and not fitted for grasping, p. 71 Raphidiid^e 

AA. Prothorax not as long as the mesothorax and metathorax combined. 

B. Hind wings broad at base and with the anal area folded like a fan when not in 

use. p. 68 Sialid^e 

BB. Hind wings narrow at base and not folded like a fan when closed. 

C. Wings with very few veins and covered with whitish powder, p. 73 

Coniopterygid^; 

CC. Wings with numerous veins and not covered with powder. 

D. Antennae gradually enlarged towards the end or filiform with a terminal 
knob. 
E. Antennae short; wings with an elongate cell behind the point of fusion 

of veins Sc and R x . p. 70 Myrmeleonid^e 

EE. Antennae long; wings without an elongate cell behind the point* of 

fusion of veins Sc and Ri. p. 73 AscalaphiD/E 

DD. Antennae not enlarged towards the end. 

E. Male with pectinate antennae; female with an exserted ovipositor. 

p. 7 2 •.■••: Dilarid^e 

EE. Antennae not pectinate in either sex; female without exserted ovi- 
positor. 
F. Radius of the fore wings with apparently two or more sectors. 

G. Radius of the fore wings with apparently two sectors, one of which is 

vein R.2+3 and the other vein R 4 +5. p. 72 Sympherobiid^e 

GG. Radius of the fore wings with three or more sectors. Veins R 4 
and R 5 arise separately from vein Ri; one or more definitive acces- 
sory branches of the radius of the fore wings present, p. 72 

• • HeMEROBIIDjE 

FF. Radius of the fore wings with a single sector. 

G. Radial sector of the fore wings without definitive accessory veins 
although marginal accessory veins are present, p. 72 .... Sisyrid^e 
GG. Radial sector of fore wings with definitive accessory veins. 
H. Transverse veins between the costa and subcosta simple, p. 69 

Chrysopid^e 

HH. Many of the transverse veins between the costa and subcosta 
forked. 

I. Humeral cross-vein recurved and branched; first radio-medial 
cross- vein of the hind wings longitudinal and sigmoid, p. 73 

POLYSTCECHOTIDiE 

II. Humeral cross- vein not recurved; first radio-medial cross- vein 
of the hind wings transverse, p. 73 Berothid^e 

Of the foregoing families but three are of common enough interest to 
justify any extended discussion in this brief work. These are the Sialidae 
which embraces the horned Corydalus and the fish-flies, the Myrmelionidae 
which includes the curious ant-lions, and the Chrysopidae or lacewing-flies. 
The lesser known families are grouped at the end of the chapter. A more 
extended discussion of them may be found in "An Introduction to 
Entomology" by J. H. Comstock. 


68 


THE STUDY OF INSECTS 


Family Sialid.-e 
The Sialids 

The members of the Sialidrc differ greatly in size and appearance; 
but they agree in having the hind wings broad at the base with the anal 
area folded like a fan when not in use. In this respect they differ from 
all other Neuroptcra. 

The larva? are aquatic, predatory, and possess paired, lateral fi la- 
ments on most or on all of the abdominal segments. They leave the 
water when full-grown and transform in earthen cells on the banks of 
the streams or lakes in which they lived as larvae. The eggs are deposited 
in clusters on any convenient support near the water, in such situations 
that the young larvae can easily find access to the water. The adults 
fly but little; they are most often found resting on some support near 
the water, with the wings folded over the abdomen. 

The smoky alder-fly, Sialis infumdta, is a dusky-brownish small 
insect with a wing-expanse of about one inch. Its eggs are laid in 
patches on objects near or over the water. The larva lives beneath 
stones in swiftly flowing streams. It has paired lateral filaments on the 


Fig. no. — Larva of 
the smoky alder-fly. 


Fig. in. — Corydalus cornulus. 


Fig. ii2. — Corydalus cor- 
nuius, larva. 


first seven abdominal segments and the last abdominal segment is pro- 
longed into a tapering lash-like filament (Fig. no). 

The species that is most likely to attract attention is the horned 
corydalus, Corydalus cornutus. This is a magnificent insect, which has a 
wing-expanse of from four to nearly five and a half inches. Figure in 
represents the male, which has remarkably long mandibles. The female 


NEUROPTERA 


69 


resembles the male, except that the mandibles are comparatively short. 
The larva? are called dobsons or hellgrammites by anglers and are used by 
them for bait, especially for bass. Figure 112 represents a full-grown 
dobson, natural size. These larvae live under stones in the beds of 
streams. They are most abundant where the water flows swiftest. They 
are carnivorous, feeding upon the nymphs of stoneflies, mayflies, and 
other insects. When about two years and eleven months old, the larva 
leaves the water, and makes a cell under a stone or some other object on 
or near the bank of the stream. This occurs during the early part of 
the summer; here the larva changes to a pupa. In about a month after 
the larva leaves the water the adult insect appears. The eggs are then soon 
laid; these are attached to stones or other objects overhanging the water. 
They are laid in blotch-like masses, which are chalky-white in color, and 
measure from half an inch to nearly an inch in diameter. A single mass 
contains from two thousand to three thousand eggs. When the larvae 
hatch they at once find their way into the water, where they remain until 
full-grown. 

There are other common species of the family which closely resemble 
Corydalus but are smaller, the larger ones measuring less than two and a 
half inches in length, and having a wing- expanse of not more than four 
inches. 

The comb-horned fish-fly Chaidiodes pectinicomis, has serrate antennae 
and grayish wings while a closely related fish-fly, Nigronia serricornis, 
also with serrate antennae, has darker, more brownish wings, spotted with 
white dots. 


Family Chrysopid^e 
The Lacewing-flies or Aphis-lions 

The family Chrysopidae includes the insects commonly known as 
lacewing-flies; these and their larvae, the aphis-lions, are common and 
well-known insects; they are found upon herbage and the foliage of 
shrubs and trees throughout the 
summer months (Fig. 113). 

The adults are easily recog- 
nized by their delicate lace-like 
wings (Fig. 114) and their green 
or yellowish-green color. Their 
eyes are large and shine like 
molten gold when alive. They 
are often called golden-eyed flies; 
and because some of them when 
handled emit a disagreeable odor 
they have been called stink-flies, 
an undesirable name for such 
beautiful insects. 

The larvae of the lacewing- 
flies are known as aphis-lions, 
because they feed upon aphids; 
they are found on the foliage of 


7o 


THE STUDY OF INSECTS 


plants infested by these pests ; they also feed upon other small insects and 
the eggs of insects; they are spindle-shaped (Fig. 113) and are furnished 
with piercing and sucking mouth-parts like those of ant-lions. 

Nearly all aphis-lions arc naked ; but a few species cover themselves 
with the skins of their victims and other debris. 

The cocoons are generally found on the lower sides of leaves or on the 
supports of plants; they arc spherical and white and composed of dense 
layers of silk. In order to emerge the insect cuts a circular lid from one side 
of the cocoon; this is done by the pupa by means of its mandibles. After 
emerging from its cocoon, the pupa crawls about for a short time before 
changing to the adult state. 


Fig. 1 1 a. — Fore wing of a lace-wing fly, Chrysopa. 

The adults are often attracted to lights at night. A remarkable fact 
in the life-history of these insects is the way in which the female cares 
for her eggs. When about to lay an egg she emits from the end of her 
body a minute drop of a tenacious substance; this she applies to the 
object on which she is standing and then draws it out into a slender 
thread by lifting the abdomen; then an egg is placed on the summit of 
this thread, which dries at once and firmly holds the egg in mid-air. 

The eggs are often laid in groups which appear like a tiny forest of 
white stems with a shining ball at the summit of each. 


Family Myrmeleonid^e 
The Ant-lions 

The members of the family Myrmeleonidae are commonly known as 
ant-lions. This name was suggested by the fact that the larvae of the 

best-known species, those 
that dig pitfalls, feed 
chiefly on ants. 

The adults are graceful 

creatures. The body is 

long and slender (Fig. 

115); the antennas are 

/ \ \J short and enlarged to- 

jj6«a BLj'^ tVjL// wards the end; the wings 

\3k ^P* eKtL are * OT1 S an d narrow and 

delicate in structure. 

The larvas have broad 

Fro. I1S .- Larva, cocoon with pupa-skin projecting, and adult of f nC |. SOmewhat depressed 

an Ant-lion. bodies which taper to- 


NEUROPTERA 71 

wards each end (Fig. 115). The mouth-parts are large and powerful and 
are of the piercing and sucking type; they are described on page 66. 
The pupa state is passed in a spherical cocoon, made of sand fastened to- 
gether with silk, and neatly lined with the same material (Fig. 115). 

The life-histories of comparatively few of the species are known; 
but certain species, the larvae of which dig pitfalls in sandy places, have 
attracted much attention since the earliest days of entomology. 

Ant-lions are much more common in the southern and southwestern 
States than they are in the North. The pitfalls of the larvae are usually 
found in sandy places that are protected from rain, as beneath buildings 
or overhanging rocks. In making these pitfalls the sand is thrown out 
by an upward jerk of the head, this part of the body serving as a shovel. 
The pits differ greatly in depth, according to the nature of the soil in 
which they are made. Their sides are as steep as the sand will lie. 
When an ant or other wingless insect 
steps upon the brink of one of these 
pits, the sand crumbles beneath its 
feet, and it is precipitated into the 
jaws of the ant-lion, which is buried 
in the sand, with its jaws at the 
bottom of the pit (Fig. 116). In case 
the ant does not fall to the bottom of „. , „ , ,. 

,. •, ,1 ,1- 1 • .,1 riG. 116. — Pitfall of an Ant-lion. 

the pit, the ant-lion undermines it by 

throwing out some sand beneath it. These larvae can be easily kept in 

a dish of sand, and their habits watched. 

The most common ant-lion in the North is Myrmeleon immaculatus ; 
the larva of this species makes a pitfall. 

For a fuller account of the following families of the Neuroptera the 
student is referred to "An Introduction to Entomology" by John Henry 
Comstock. 

Family Raphidiid^e 

The Snake-flies 

i e l% e . ll7 '~ Raphidia ' The members of the Raphidiidse are found in this 
country only in the far West. They are strange- 
appearing insects, the prothorax being greatly elongated, like the neck 
of a camel (Fig. 117). 

Family Mantispidje 

The Mantis-like Nenropterons 

The members of the Mantispidae are 
even more strange in appearance than are 
those of the preceding family. Here, as in 
that family, the prothorax is greatly elon- 
gated; but the members of this family can 
be easily recognized by their remarkable fore 
legs, which are greatly enlarged and resemble 
those of the praying mantes in form (Fig\ , FlG -. " 8 - ~ M «»<«/><j. in the specimen 

TT n\ <t>i 1 £,, i/- . . ° figured the fore legs were twisted somewhat 

T 15;. I nese legs are fitted tor Seizing prey. in order to show the form of the parts. 


72 


THE STUDY OF INSECTS 


Family Sisyrid^e 

The Spongilla-flies 

The Sisyridae include a very limited number of small, smoky brown 
insects. They are called spongilla-flies because the larvae live as paras- 
ites in fresh-water sponges, the typical genus of which is Spongilla. 

Family Sympherobiid^e 

The Sympherobiids 

This family includes certain insects which were formerly classed with 
the Hemerobiidae but which exhibit a type of specialization of the wings 
that is quite different from that which is distinctively characteristic of 
that family. 

Family Hemerobiidae 

The Hemerobiids 

The Hemerobiidae include insects of moderate size; in most of our 
species the wing-expanse is between ^ and | of an inch; in one species 
of Megalomus it is only \ inch. In most of the species the body is 


Fig. iiq. — Fore wing of Hemerobius. 

brown or blackish and is often marked with yellow; in some the body 
is pale yellow. The wings are usually hyaline or pale yellowish (Fig. 119). 

Family Dilarid.e 

The Dilaridae is a small family, representatives of which are found 
chiefly in the Old World. In this family the antennae of the male are 
pectinate; and the female is furnished with an exserted ovipositor. 

A single rare species, Dllar americdnus, has been found in North Amer- 
ica; and of this only a single female individual is known of which the 
body is scarcely £ of an inch in length. 


NEUROPTERA 


73 


Family Polysixechotid,e 

The family Polystoechotidas was established to receive the genus 
Polystoeckotes, of which only two species, both 
American, are known. These are larger in- 
sects than are the members of the allied 
families, measuring in wing-expanse from if 
inches to 3 inches. They are nocturnal in 

habits (Fig. I2o). Fig. 120. — Polystcecholes punctatus. 


Family Berothid^e 

The Berothidas is a small family, which is represented in North Amer- 
ica by a single genus, Lomamyia, of which only two species are known. 

Family Ascalaphid^e 
The Ascalaphids 


Fig. 121a. — Larva 
of an Ascalaphid. 


Fig. 121. — An Ascalaphid. 

The family Ascalaphidas is quite closely allied to the 
Myrmeleonidas ; but the members of this family can 
usually be distinguished from myrmeleonids by the greater 
length of the antennas. The larvae resemble ant-lions in 
form of the body and possess the same type of mouth- 
parts (Fig. 121). 


Family Coniopterygid^e 

The Mealy-winged Neuropterons 

The Coniopterygidas is a family of limited extent; and it includes 
only small insects, the smallest of the Neuroptera; the described Amer- 
ican species measure only 3 mm. or less in length. They have the body 
and wings covered by a whitish powder. 


CHAPTER IX 
ORDER EPHEMERIDA * 


The Mayflies 

The members of this order have delicate membranous wings, triangular in 
outline and with many cross-veins and usually extra longitudinal veins; 
the hind wings are smaller than the fore wings and are sometimes wanting. 
The mouth-parts of the adidts are vestigial; those of the nymphs are fitted for 
chewing. The metamorphosis is incomplete. 

The name of this order is from the Greek word ephemeros, lasting but 
a day. It was given to these insects on account of the shortness of their 

lives after reaching the adult state. The mayflies 
are easily distinguished from other net-winged 
insects by the peculiar shape of the wings and the 
relative sizes of the two pairs (Fig. 122). 

The mouth-parts are nearly wanting, as these 
insects eat nothing in the adult state; the an- 
tennas are very small ; the abdomen is long, soft, 
and terminated by two or three many-jointed, 
thread-like appendages. 

Mayflies exhibit a remarkable peculiarity in 
their development. After the insect leaves the 
water and has apparently assumed the adult form, 
that is, after the wings have become fully ex- 
panded, it molts again. These are the only insects 
that molt after they have attained functional 
wings. The term subimago is applied to the 
instar between the nymph and the final form of 
the insect, the imago. With some species the 
fig. 122. — Mayfly. duration of the subimago stage is only a few 

minutes ; the insect molts on leaving the water ; flies a short distance ; and 
molts again. In others this stage lasts twenty-four hours or more 

What is spoken of as the brief or ephemeral life of the mayflies is 
true only of their existence in the adult state. Strictly speaking, the 
mayflies are long-lived insects. A few species pass through their life- 
cycle in a few weeks in midsummer; but as a rule one, two or three 
years are required for the development of a generation. The greater part 
of this time is passed, however, beneath the surface of the water as a 
nymph and after the insect emerges and assumes the adult form its 
existence is very brief. With many species the individuals leave the 
water, molt twice, mate, lay their eggs and die in the course of an evening 
or early morning. In the case of other species the adults may live several 
days; yet the lives of these are short compared with those of other in- 
sects. 

* EphemeYida, Ephemera: ephemeron (k^rinepov), a Mayfly. 
74 


EPHEMERIDA 75 

The eggs of mayflies are laid on or in the water. Either the female 
alights at intervals on the water to wash off the eggs or she cieeps down 
into the water to lay her eggs upon the undersides of stones. In either 
case the eggs finally rest in the water and hatch there into the nymphs 
which always live in the water. The nymphs breathe by means of tra- 
cheal gills which are usually situated along each side of the abdomen. 
They are usually active and live on bits of plant food found in the 
water. Some burrow in the bottom silt, others climb actively over green 
vegetation in the water, while others live in swiftly flowing water where 
they cling closely to submerged logs and stones. 

With many species of mayflies there is great uniformity in the date 
of maturing of the individuals. Thus immense swarms of them will 
leave the water at about the same time, and in the course of a few days 
pass away, this being the only appearance of the species until another 
generation has been developed. The great swarms of "lakeflies," 
Ephemera simulans, which appear along our northern lakes about the 
third week of July, afford good illustration of this peculiarity. 

Family Ephemeridje 

The Mayflies 

The order Ephemerida includes a single family, the Ephemeridae; 
the characteristics of this family, therefore, are those of the order, which 
are given above. 

The appearance and habits of the mayflies are certainly well known 
by those who live in the vicinity of streams, ponds, or lakes. 

In river or lake towns, during the warm evenings of late spring or 
early summer, the electric lights or street lamps are often darkened by 
myriads of insects that dash against them, and the pavements are made 
slippery by their dead bodies which have been trampled under foot. 
They are not the ordinary night-flying moths: if an individual of the 
thousands that cling to the posts and buildings in the vicinity of the 
light be examined, it will prove to be a delicate creature with dainty, 
trembling wings and two or three long, thread-like organs on the end of 
its body; the body itself is so transparent 
that the blood within can be seen pulsating. 
The front wings are large and finely netted, 
and the hind wings are small or absent (Fig. 
123). So fragile are these pale beings that 
they seem like phantoms rather than real 
fig 12? —Canis i nsec ts. No wonder that poets have sung of 
a two-winged May- them as the creatures that live only a day. 
It is true that their winged existence lasts 
often only a day or even a few hours; but they have an- fig. 124. — Nymph 
other life, of which the poet knows nothing. Down on the of Mayfly - 
bottom of a stream, feeding on mud, water-plants, or small insects, 
lives a little nymph with delicate, fringed gills along its sides and two or 
three long, many-jointed, and often feathery appendages on the end of the 
body (Fig. 124). It has strong legs and can both walk and swim. After 
about the ninth molt — there may be twenty molts in all — there appear 
on its thorax four little sacs which are the beginnings of wings; with each 


76 


THE STUDY OF INSECTS 


molt these grow larger, until finally the last skin of the water-nymph is shed, 
and gills and mouth-parts arc all left behind, and the insect comes forth, a 
winged mayfly. But there is still another change to be undergone. The 
insect has not yet reached the adult state. After flying a short distance it 
alights and sheds its skin again, a thin layer coming off from all parts of its 
body, even from its wings. After this the delicate creature is more fragile 
than before. It now has but one duty to perform in its brief life in the air, 
and that is to lay its eggs. These are sometimes laid on the surface of the 
water, and sometimes the mother wraps her wings about her like a diving- 
bell and goes down into the water and deposits her eggs on stones and then 
dies. 


This excellent illustration after Needham, shows a characteristic may- 
fly (A), with its long front legs, triangular wings, and slender caudal 
setae. It has transformed from the nymph (B), which spent its long life 
in the water where it obtained air by means of the feathery gills along 
the sides of the abdomen. 


CHAPTER X 
ORDER ODONATA* 


Fig. 125. — A dragonfly. 


The Dragon flies and the Damselflies 

The members of this order have jour membranous wings, which are 
finely netted with veins; the hind wings are as large as or larger than the 
fore wings; and each wing 
has near the middle of the 
costal margin a joint-like 
structure, the nodus. There 
are no wingless species. 
The mouth-parts are formed 
for chewing. The metamor- 
phosis is incomplete. 

Dragonflies and damsel- 
flies are very common in- 
sects in the vicinity of 
streams, ponds, and lakes; 
they are well known to all 
who frequent such places. 
The dragonflies, especially, 
attract attention on ac- 
count of their large size (Fig. 125) and rapid flight, back and forth, over the 
water and the shores; the damselflies (Fig. 128) are less likely to be noticed, 
on account of their less vigorous flight. 

Suborder ANISOPTERA f 

The Dragonflies 

The dragonflies constitute a natural division of the Odonata, the sub- 
order, Anisoptera. The wings of dragonflies are usually extended hori- 
zontally when they are at rest and the hind wings are as large and often 
are larger than the front ones. The compound eyes are very large, often 
occupying most of the surface of the head. In many cases the upper 
facets of each eye are larger than the lower ones. It is probable that in 
such eyes the part of the eye with the large facets is for night vision 
while the part of the eye with the small facets is for day seeing. Most 
dragonflies appear to have very keen sight for they follow and catch 
mosquitoes, midges and other small flies while on the wing, much as a 
hawk swoops downward and captures a weaker bird. But dragonflies are 
entirely innocent of any harm to mankind. They neither sew up people's 

* Odonata: odous (65ous). a tooth. 

f Anisfiptera: anisos (avuros), unequal; pteron (irrepov), a wing. 

11 


78 


THE STUDY OF INSECTS 


ears, as northern children think; nor bring dead snakes to life, as colored 
people in the South believe; but they are very fierce enemies to their 
insect kindred. Their long, narrow, closely-netted wings are strong, carry- 
ing them swiftly; and their jaws are powerful, and their appetites good; 
so ii is an unfortunate insect that falls in their way. 

The nymphs of dragonflies are stout-bodied creatures usually resting 
among the weeds in the water or in the silt at the bottom of a pond or 
stream. The abdomen is wide and there are no external gills. They are 
aquatic, for the female dragonflies lay their eggs either 
in the stems of water-plants, in submerged logs, or in 
wet mud or they simply fly down to the water and 
wash off their eggs from the abdomen or, alighting on a 
plant-stem, they push the long abdomen down into the 
water and lay a mass of eggs on a submerged stem or 
leaf. In any case when the eggs hatch the nymphs find 
themselves in the water and at once swim off and hunt 
for some smaller creatures to eat, for they are all 
carnivorous and ferocious. 

They have strong legs and big jaws, and are real 
insect ogres. The lower lip when extended reaches far 
out, and is armed with powerful hooks with which to 
grab their prey (Fig. 126) ; but when folded up it is so 
large that it is called a mask and gives the insect's face 
a comical resemblance to that of a bull-dog. These 
nymphs have a peculiar method of breathing. The 
caudal end of the alimentary canal is enlarged into a 
chamber and lined with tracheae. The 
nymph alternately draws water into 
this cavity and expels it; and thus 
the air in these tracheae is purified, 
this part of the alimentary canal 
acting as a tracheal gill. This process also helps the 
insect in swimming, for the water may be expelled with 
such force that the whole body is sent forward. 

When the nymph of a dragonfly is fully grown it 
leaves the water to transform. The skin of the nymph 
splits open on the back of the thorax and head, and 
the adult emerges, leaving the empty skin of the nymph 
clinging to the object upon which the transformation 
took place (Fig. 127). 

There are two families of dragonflies, the Mschnidce, 
and the Libclhdidce. 


Fig. 126. — Under 
side of head of a 
nymph of a damsel- 
fly with labium un- 
folded. (After Sharp.) 


Family ^schnid^ 


Fig. 127. — Exuviae of 
nymph of dragonfly. 


The eeschnids are mostly large species; among them are the largest, 
fleetest, and most voracious of our dragonflies. Some of them roam far 
from water and are commonly seen coursing over lawns in the evening 
twilight; but most of them fly over clear water. Some of the adults are 
marked with bright blues and greens. The nymphs eat nearly any ani- 
mal they can capture and hold. 


DON ATA 


79 


Family Libellulid^e 

This is a large family including many of our commonest and best- 
known species of dragonflies; many of them are familiar figures flying 
over ponds and ditches and by roadsides. Most of them are of well- 
sustained flight, and are seen continually hovering over the surface of 
still water; this suggested the common name skimmers which has been 
applied to them. 

Suborder ZYGOPTERA * 


The Damselflies 

The damselflies differ so much from the dragonflies and are so much 
like each other that they also constitute a well-defined suborder, Zygop- 
tera, of the Odonata. 

The two pairs of wings of 

the damselflies are similar in 

form and are either folded 

parallel with the abdomen when 

at rest or are uptilted in a 

vertical position (Fig. 128). 

The head is small and the eyes 

project on each side while the 

females possess an ovipositor 

by means of which they place 

their eggs in the stems of 

aquatic plants sometimes be- 
neath the water. 

Unlike the dragonflies, the 

damselflies are comparatively 

slow and feeble of flight al- 
though they are graceful in 

their movements. They are 

found along the margins of 

streams and ponds in which the 
nymphs pass their lives. 

Many of the damselflies are very attractive because of their bright 
blue or green metallic colors. 

The nymphs of the damselflies are slender, long-bodied creatures 
which cling to weeds in the water (Fig. 129). The abdomen is narrow 
and bears at the caudal end three flat, leaf -like tracheal gills set on edge 
in a vertical position. 

There are two families of the damselflies, the Agrionidce and the 
Ccenagrionidce. 

Family Agrionidce 

Here belong the most -beautiful of our damselflies, whose metallic 
blue or green colors are sure to attract attention. They are feeble in 
* Zygoptera: zygon (^vyov), yoke; pier on (wTepov), a wing. 


Fig. 128. — A damselfly. 


Fig. i2g. — Nymph of 
a damselfly. 


8o 


THE STUDY OF INSECTS 


flight and do not go far from the banks of the pond or stream in which 
they were developed. 

Family Cosnagrionid^e 

The members of this family are easily recognized by the shape of 
their wings, which are long, narrow, and very distinctly petiolate. 

To this family belong the smallest of our damselflies; but while our 
species are of small or moderate size, there exist in the tropics species 
that are the largest of the Odonata. Some of our species are dull in 
color; but many are brilliant, being colored with green, blue, or yellow. 
This family includes the greater number of our damselflies. 


Cn 2 Cm 

Fig. 129a. — Wings of a dragonfly. 


This is an illustration of the fore and hind wings of a dragonfly, en- 
larged to show the fine network of veins with the nodus, n, at the middle 
of the costal margin and the black area near the apex of the wing, known 
as the stigma. 


CHAPTER XI 
ORDER PLECOPTERA* 

The Stoneflies 

The members of this order have four membranous wings, with compara- 
tively few or with many cross-veins; in most of the forms the hind wings are 
much larger than the fore ivings, and are folded in plaits and lie upon the 
abdomen when at rest. The mouth-parts are of the biting type of structure, 
but are frequently undeveloped in the adults. The metamorphosis is in- 
complete. 

The stoneflies are common insects in the vicinity of rapid streams 
and on wave-washed rocky shores of lakes; but they attract little atten- 
tion on account of their inconspicuous colors and secretive habits. They 
get their name, stoneflies, from the fact that the nymphs are abundant 
under stones in the beds of streams. 

The body of an adult stonefly is flattened and the end of the abdomen 
in most species, bears two, many-segmented bristles. The antennas are 
also long, tapering and many-segmented. The mouth-parts are usually 
greatly reduced. Indeed, in some, 
the mandibles are almost membra- 
nous and of little use as chewing 
organs. In other forms they are 
firm and well fitted for biting. This 
is especially true of certain species 
of the genus, Tceniopteryx. One 
species of this genus, T. pacifica, 
known as the "salmon fly" has be- 
come a pest in the Wenatchee 
Valley in Washington because it 
eats into the swelling buds of 
apricots, peaches, and plums and 
often destroys them. 

Adult stoneflies are not partic- 
ularly attractive insects for most of Fig. 130. — a stonefly. 
them are of sober hues, black, brown, or grav, although a few which 
frequent the foliage of plants are green (Fig. 130). As a rule, they are not 
strong fliers and are usually found crawling about on stones or on plants 
near streams. Interestingly enough, several of the smaller forms appear 
early during warm days in February and March while the snow is still on 
the ground. Several small species formerly of the genus, Capnia, but now 
renamed Allocapma, are early spring appearing individuals. A very 
common one, A. pygmcea, which is dark brown to black and only about 
4 of an inch long, is known as the snow-fly because it appears on the 
* PlecSptera: plecos (ttUkos), plaited; pteron {-wrtpov), a wing. 

81 


82 


THE STUDY OF INSECTS 


snow during warm days in winter and often enters the house where it 
may be found crawling on the window-panes. 

The nymphs of stonefiies cling to the undersides of flat stones in 
swiftly flowing streams. They are flat creatures from one-half inch or 
less to one and one-half inches in length. They 
cling so closely and are so nearly the color of the 
stone that they look almost like fossils. Their 
antennas and caudal bristles and three legs on each 
side extend out like the rays of a star; the six soft 
clumps of white hair-like gills, one behind each leg, 
alone show that they are not engraved upon the 
stone (Fig. 131). These nymphs of the stonefiies 
are the favorite food of fishes, especially of brook 
trout. If a nymph is fortunate enough to escape 
the fate of being a luncheon for fish, when it is full- 
grown it crawls forth from the water and transforms 
to an adult stonefly. The east nymph-skins are 
common objects on the banks of streams which 
these insects inhabit. 

The tracheal gills of some nymphs are borne 
either on the underside of the head or on the abdo- 
men while some nymphs possess no tracheal gills 
fig. 131. — Nymph of stone- whatever, their supply of air being absorbed through 
fly - the skin. 

According to a recent classification of this order, that of Tillyard, it 
includes seven families; but only four of these families are represented in 
our fauna. The four families of our fauna can be separated by the 
following table. Most of our species belong to the Perlidae, 

A. Anal area of the fore wings with two or more series of cross-veins. 

Pteronarcid^e 

AA. Anal area of the fore wings with not more than a single series of cross-veins, 
usually with no cross-veins beyond the basal anal cell. 
B. Media of the fore wings separating from radius gradually, the two forming 

a sharp angle Perlidae 

BB. Media of the fore wings separating from radius abruptly, the two forming a 
blunt angle. 
C. Anal area of the fore wings with a forked vein arising from the basal anal 

cell. Cerci vestigial Nemourid^e 

CC. Anal area of the fore wings with only simple veins arising from the basal 
anal cell. Cerci well developed Capniid^e 


CHAPTER XII 
ORDER CORRODENTIA* 

The Psocids and the Book-lice 


# • \ 


Fig. 13: 


Psoius venosus. 


The winged members of this order have four membranous wings, with the 
veins prominent, but with comparatively few cross-veins; the fore wings are 
larger than the hind wings; and both pairs when not in use are placed roof- 
like over the body, being almost vertical, and not folded in plaits. The 
mouth-parts are formed for chewing. The metamorphosis is incomplete. 

The best-known representatives of this order are the minute, soft- 
bodied insects which are common in old papers, books, and neglected col- 
lections and which have received the popular 
name of book-lice. These low, wingless creatures 
form, however, but a small part of the order. 
The more typical winged forms (Fig. 132) bear 
a strong resemblance to plant-lice or aphids. 
The body is oval, the head free, and the protho- 
rax small. The fore wings are larger than the 
hind wings ; and both pairs when not in use are 
placed roof-like over the body, being almost 
vertical, and not folded in plaits. The mouth- 
parts are plainly chewing. The mandibles are of the ordinary, strong, 
heavy, biting type. The maxillas consist each of a body piece, a weak ter- 
minal lobe, and a four-segmented palpus. 

The venation of the wings is characteristic in this order, see page 84. 
The venation is more or less reduced; but its most characteristic feature 
is the bracing of the wing by anastomoses of the principal veins instead 
of by cross-veins, although there are one or two cross-veins in some species. 

The Corrodentia of the United States and Canada represent two fam- 
ilies, which can be separated as follows. 

A. Wings well developed; ocelli present Psocids 

AA. Wings absent or vestigial; ocelli absent Atropine 

Family Psocids 

The Psocids 

The family Psocidae includes the more typical members of the Corro- 
dentia, those in which the wings are well developed (Fig. 132). Usually 
the wings extend much beyond the end of the abdomen; but short- 
winged forms occur in species which ordinarily are long-winged. Of 
course the young of all are wingless, and there is a gradual development 
as the insect matures. 

* Corrodentia: Latin corrodens, gnawing. 
83 


8 4 


THE STUDY OF INSECTS 


The psocids occur upon the trunks and leaves of trees, and on stones, 
walls, and fences. They feed upon lichens, fungi, and probably other 
dry vegetable matter. 

The eggs are laid in heaps on leaves, branches, and the bark of trunks 
of trees. The female covers them with a tissue of threads, the silk of 
which is spun from the labium. 


Family Atropid^e 

The Book-lice and their Allies 

The most commonly observed species of this family are those known 
as book-lice, which are the minute soft-bodied insects often 
found in old books (Fig. 133). 

Take down from the shelf a time-yellowed book and 
open its neglected leaves and watch the pale tiny creatures 
that scurry across its pages; examine one of them with a 
lens, look well at its alert, knowing, black eyes, and we are 
sure you will believe that it is in search of real literature and 
not merely a feeder upon paper, as we are taught. Anyway, 
scientists have concluded that these insects look wise 
enough to bear the name Troctes divinatorius. Another 
species with small convex scales representing the front wings is Atropos 
pulsatoria. It is pale yellowish white and only ^ s of an inch in length. 

The book-lice feed on the paste in bookbindings, wall-paper and 
photographs. One species sometimes occurs in enormous numbers in 
husk or straw mattresses, in which case it is very annoying. 


Fig. 133. — A book 
louse. 


/?4+5 


Fig. 133a. — Wings of a psocid. 


These enlarged wings of a psocid illustrate the anastomosing of the 
principal veins, a form of structure which strengthens the wings with- 
out the necessity of cross-veins. 


CHAPTER XIII 
ORDER MALLOPHAGA* 

The Bird-lice 

The members of this order are wingless parasitic insects with chewing 
mouth-parts; cerci absent. Their development is without metamorphosis. 

The bird-lice are small wingless insects. The more common species 
range from -£- s of an inch to | of an inch in length. The bodies of 
these insects are flattened and usually have broad distinct heads with the 
antennas short and either exposed or hidden in grooves on the underside 
of the head. Bird-lice vary in color from almost white to yellow, tan, 
brown or nearly black with or without distinctive markings. The mouth- 
parts are on the underside of the head. The mandibles are large and 
prominent and the clypeus is enlarged into a conspicuous flap. Degen- 
erate eyes are present on the margins of the head. 

The bird-lice resemble the true lice in form and in being parasitic 
but they feed upon hair, feathers and dermal scales, while the true lice 
(Anoplura) have sucking mouth -parts and feed upon blood. 

The Mallophaga infest chiefly birds and on this account the term, 
bird-lice, is applied to the entire group; a few forms, however, are para- 
sitic upon mammals. For the most part the tarsi of those species that 
live upon mammals have but one claw which can be clamped against the 
tibia thus forming a structure well adapted for clinging to hairs. Those 
species which infest birds have two claws on the tarsi which are better 
adapted to running among feathers. The white eggs of the bird-lice are 
glued singly or in groups to the feathers and the development takes 
place on the body of the host. 

Bird-lice injure their hosts through the constant irritation which 
they cause by feeding on the dermal scales and by scratching the skin 
with their sharp claws during their incessant movements over the body 
of the host. It is to free themselves from these pests that birds wallow 
in dust. When poultry are kept in closed houses they should be provided 
with a dust bath. In addition the fowls should be treated with a pinch 
of sodium fluoride on the head, beneath each wing, on the back and 
underside of the abdomen, and two or three pinches beneath the tail 
feathers. It has also lately been discovered that nicotine-sulphate 
smeared on the perches just before the fowls go to roost will destroy all 
of the lice. 

The body-louse of the hen, Menopon biseriatum, is the largest louse 
on the hen; it is about -^ of an inch in length. It is yellowish in color 
and is found all over the body of the hen and is probably the most 

* Mallophaga: mallos (na\\6s), wool; phagein (4>aytli>) , to eat. 

85 


86 THE STUDY OF INSECTS 

serious louse on older chickens and young fowls (Fig. 134). It lays its eggs 


Fig. 135. — Goniodes stylifer. 
(From Law.) 


Fig. 136. — Tri 
chodectes scalaris 
(From Law.) 


The body-louse of the 


in clusters at the bases of feathers, especially 
about the vent of its host. 

The feather louse, Menopon pallidum, is 
another louse on the hen. It frequents the 
feathers commonly, although it is found on 
the skin of its host. 

The large turkey louse, Goniodes stylifer, 
is common on the turkey. It frequents the 
feathers on various parts of the body, espe- 
cially on the neck and breast (Fig. 135). 

Another and smaller species which in- 
fests the ox is known as, Trichodectes 
scalaris (Fig. 136). 


CHAPTER XIV 
ORDER EMBIIDINA* 

The Embiids 

This order is composed of small and feeble insects in which the body is 
elongate and depressed. The winged members of the order have two pairs 
of wings, which are quite similar in form and structure; they are mem- 
branous, extremely delicate, and folded on the back when at rest; the vena- 
tion of the wings is considerably reduced. The mouth-parts are formed for 
chewing. Cerci are present and consist each of two segments. The meta- 
morphosis may be considered as incomplete. 

This is a small order of insects, only 61 species being listed in a late 
monograph of the order. Only the males are winged and some species of 
these are wingless. The wings are usually rather long but have com- 


Fig. 137. — Embia sabulosa, male. (After Enderlein.) 

paratively few veins. Brownish bands run lengthwise of the wings along 
the courses of the longitudinal veins. The antennas are filiform and com- 
posed of 16 to 32 segments, while ocelli are wanting (Figs. 137 and 138). 

The metamorphosis of the winged males is more than incomplete and 
less than complete. It is peculiar because of this intermediate character. 

The embiids are small insects and not often seen. They live in silken 
burrows or galleries made beneath stones or other objects on the ground 
and sometimes in old decayed logs. Often there is extensive and con- 
* Embiidina: Embiidae, Embia, embios (e/j/3ios), lively. 
87 


88 THE STUDY OF INSECTS 

spicuous webbing of silk about the haunts and runways of the insects. 
There seems to be a difference of opinion regarding the position of the 


Fig. 138. — Wing of an embiid, enlarged. 

silk glands and the source of the silk. Further study of the production 
of the silk should be made. 

The embiids are widely distributed in the warmer parts of the world. 
A few species have been found in Florida, Texas, and California. They 
apparently live on decayed organic matter obtained with their chewing 
mouth-parts. 


Fig. 138a. — A female embiid. 

A female embiid, shown in this illustration, is wingless but has long, 
slender antennae. It must be remembered, however, that this insect is 
very small — it is only about § of an inch in length. 


CHAPTER XV 
ORDER THYSANOPTERA * 


The Thrips 

The members of this order are minute insects with wings or wingless. 
The winged species have jour wings; these are similar in form, long, narrow, 
membranous, not plaited, with but few or with no veins, and not commonly 
with cross-veins; they are fringed with long hairs, and in some species are 
armed with spines along the veins or along the lines from which veins have 
disappeared. The mouth-parts are formed for piercing and sucking. The 
tarsi are usually two- jointed and are bladder-like at the tip. The metamor- 
phosis is incomplete, but deviates from the usual type. 

The species of thrips occurring in our fauna are of small size, rarely 
more than ^ to \ of an inch in length. They can be obtained easily, 
however, from various flowers, especially those of the daisy and clover. 
Ordinarily it is only necessary to pull apart one of these flowers to find 


Fig. 139. — Thrips. 


Fig. 140. ■ 
original. 


Fore wing of Mlothrips nasturlii. (After Jones.) The lettering is 


several thrips. They are in many cases very active insects, leaping or 
taking flight with great agility. 

The body is long (Fig. 139). The antennas are filiform or moniliform 
and consist of from six to nine segments; they are always longer than 
the head and may be two or three times as long. The compound eyes 
are large, with conspicuous facets, which are circular, oval, or reniform 
in outline. Three ocelli are usually present in the winged forms. The 
mouth-parts are fitted for piercing and sucking; they are in the form 
of a cone which encloses the piercing organs. The cone is composed of 
the clypeus, labrum, maxillary sclerites, and labium. The piercing organs 
consist of the left mandible (the right mandible is vestigial) and the 
two maxillse. The mouth-parts of the Thysanoptera bear a striking 
resemblance to those of the Hemiptera. The wings are laid horizontally 
on the back when not in use; they are very narrow, but are fringed with 
long hairs (Fig. 140). The fringing of the wings suggested the name 
Thysanoptera. 

* ThysanSptera: thysanos (dvaavoi), fringe; pier on (irrepov), a wing. 

89 


9° 


THE STUDY OF INSECTS 


In some species one or both sexes are wingless in the adult state; 
and in others, short-winged forms occur. The cerci are absent. 

The legs are well developed, but are furnished with very peculiar 
tarsi. These are usually composed of two segments; the last segment 
terminates in a cup-shaped or hoof-like end and is usually without claws. 
Fitted into the cup-shaped end of the tarsus there is a very delicate, 
protrusile, membranous lobe or bladder, which is withdrawn into the cup 
when not in use but is protruded when the tarsus is brought into contact 
with an object. This is one of the most distinctively characteristic 
features of the members of this order. It was this feature that suggested 
the name Physopoda which is applied to this order by some writers. 

In one suborder, the Terebrantia, the female has a saw-like ovipositor 
with which she cuts slits in the tissues of plants and then deposits her 
eggs therein. In the other suborder, the Tubulifera, 
the female does not have a saw-like ovipositor and 
evidently deposits her eggs on the surfaces of objects. 
The metamorphosis of thrips is interesting because 
it approaches in some respects the type of com- 
plete metamorphosis. There is a quiescent stage 
resembling a pupa preceding the imago (Fig. 141). 

The different species of thrips vary greatly in 
habits, some being injurious to vegetation, while 
others are carnivorous, feeding on aphids and other 
small insects, the eggs of insects, and mites, especially 
the "red spider." Their most important economic 
role, however, is that of pests of cultivated plants. 
The thrips that infest plants puncture the tissue of 
the plant by their piercing mouth-parts and suck out 

Fig. 141. — Last nym- ,1 
phal stage of a thrips. tne Sap. 


Suborder TEREBRANTIA 

Among those thrips having saw-like ovipositors are found the more 
important economic species. The onion thrips, Thrips tabaci, is seriously 
injurious to onions, and often attacks cucumbers, tobacco, cabbage, and 
cauliflower. 

The greenhouse thrips, Heliothrips hczmorrhoidalis, is a tropical in- 
sect, which is often a serious pest in greenhouses; it is also found out 
of doors in the milder California climate. 

The bean thrips, Heliothrips fasciattis, is a serious pest on oranges, 
alfalfa, pear trees, and various garden crops in California. 

The orange thrips, Sctrtothrips citri, is a serious orange pest in Cali- 
fornia and Arizona; it deforms the new growth of foliage and causes 
scabbing and scarring of the fruits. 

The pear thrips, Tmnothrips inebnsequens , infests pears, prunes, 
peaches, and other deciduous fruits, both in California and in the East. 
It infests the opening buds and blossoms, stunting the leaves and blast- 
ing the blossoms. 

The strawberry thrips, Franklhriella tritici, was first described as a 
pest of wheat. It is found in the flowers of almost all wild and cultivated 
plants and is the commonest and most widely distributed of all American 
species of thrips. It is especially injurious to the strawberry. 


THYSANOPTERA 


91 


Suborder TUBULIFERA 

Those thrips which lack the saw-like ovipositor are not of great eco- 
nomic importance in our country, at least. One of the more common forms 
is the mullein thrips, Neoheegeria verbasci, the black individuals of which 
may usually be found in numbers during the fall among the rosettes of 
woolly leaves of our common mullein. 

The camphor thrips, Cryptothrips floridensis , is particularly abundant 
in Florida, where it is injurious to the camphor tree, especially to those 
individuals that have been cut back or pruned severely. 


Fig. 141a. — Trillium. 


One of our fine, large species of thrips, Ctenothrips bridwelli, is found 
on trillium and mandrake. 


CHAPTER XVI 
ORDER ANOPLURA* 


The True Lice 

The members of this order are wingless parasitic insects with piercing 
and sucking mouth-parts. Their development is without metamorphosis. 
Cerci absent. 

The order Anoplura is composed of the true lice. These are small 
wingless insects, which live on the skin of mammals and suck their blood. 
They are sharply distinguished from the Mallophaga or 
bird-lice by the possession of piercing and sucking 
mouth-parts. 

The body is more or less flattened (Fig. 142). The 
head is free and horizontal. The compound eyes are 
vestigial or are wanting. There are no ocelli. The 
antennas are three-, four-, or five-jointed. The mouth 
is furnished with a fleshy, unjointed proboscis, which 
can be withdrawn into the head or extended to a con- 
siderable length. Within this proboscis are two knife- 
like stylets; and at its base, when extended, there is a 
wreath of recurved hooks. These hooks serve to anchor 
firmly the proboscis when inserted in the skin of the in- 
fested animal. 

There is a single tarsal claw, which is opposed by a 
toothed projection of the tibia, forming an efficient 
organ for clinging to the hairs of the host. The abdomen consists of nine 
segments; there are no cerci. 

The eggs of the true lice are commonly known as "nits." They are 
attached to the hairs of the host by a glue-like substance. The young 
lice resemble the adults except in size. 

The order Anoplura is a small one of not more than 100 species at the 
present time. The most familiar forms are those infesting man and the 
domestic animals, horses, cows, sheep, swine, dogs and cats. 

The three species of lice parasitic on man belong in the family Pedi- 
culidas. They have comparatively large, convex, pigmented eyes and the 
proboscis is short. 

The most common species on man is the head -louse, Pediculus capitis. 
It lives among the hairs of the head and attaches its white eggs, or 
"nits" to the hairs. It is most common on the heads of children who 
live under unsanitary conditions. 

The body-louse, Pediculus corporis, (Fig. 143), lives on the body, espe- 
cially on the chest and back. It increases enormously among soldiers who 
are unable to bathe frequently. During the world war the "cooties," as the 
* Anoplura: anoplos (avoirXos), unarmed; oura (ovpa), tail. 

92 


Fig. 142. — Louse of the 
horse. (From Law.) 


ANOPLURA 


93 


soldiers called them, were extremely troublesome. They laid their eggs on 
threads of the clothing but it was found that both lice and eggs were 
destroyed during a proper laundering process. 

The crab-louse, Phthirius pubis, which is nearly as broad as long, 
lives in the armpits and pubic regions of the body. 

The common lice on cattle, swine, dogs and cats belong to the family 
H&matopinidce. These lice have long probosces and the eyes are vestigial 
or wanting. The short-nosed ox-louse, Hosniatopinus eurystemus, (Fig. 144) 


Fig. 143. — The body louse, 
Pediculus corporis, much en- 
larged. 


Fig. 144. — E. euryster- 
nus. (From Law.l 


Fig. 14s. — The 
louse. (homLaw.) 


is found principally on the neck and shoulders of mature cattle. It is of 
a bluish-slate color and about f of an inch long. Sodium fluoride applied to 
the infested places with a tin shaker and then rubbed in among the hairs 
with the hand is an effective remedy for these cattle-lice. 

The dog-louse, Linognaihus piltferus, has a broad abdomen and a com- 
paratively short proboscis (Fig. 145). The hog-louse, Hcematopinus suis, 
is the largest louse affecting domestic animals and is common on swine, 
especially if their quarters are neglected and allowed to become un- 
reasonably filthy. 


CHAPTER XVII 
ORDER HEMIPTERA* 

The True Bugs 

The winged members of this order have four wings; the wings of the 
first pair are thickened at the base, with thinner extremities which overlap 
on the back. The mouth-parts are formed for piercing and sucking; the 
beak arises from the front part of the head. The metamorphosis is incom- 
plete. 

People who know but little regarding entomology are apt to apply 
the term bug to any kind of insect; but strictly speaking, only members 
of the order Hemiptera are bugs. 

The bugs are very common insects. Many species abound on grass 
and on the foliage of other plants; some species live on the surface of 
water; others live within water; and a few are parasitic on birds and 
mammals. 

This order is a very important one; it includes many species in- 
jurious to vegetation; among these are some of our more important 
pests of cultivated plants. On the other hand, some of the species are 
ranked among beneficial insects on account of their predacious habits; 
for many of them feed upon noxious insects. 

The name Hemiptera was suggested by the form of the front wings. 
In these the basal half is thickened so as to resemble the elytra of beetles, 
only the terminal half being wing-like. The hind wings are membranous, 
and are folded beneath the front wings. On this account the front wings 
are often termed wing-covers; they are also termed hemelytra, a word 
suggested by their structure. 

In the Hemiptera the front wings present characters much used in the 
classification of these insects; and consequently special names have been 

applied to the different parts of them. 
The thickened basal portion is com- 
posed of two pieces joined together 
at their sides; one of these is narrow 
and is the part next to the scutellum 
when 1;he wings are closed; this is 
distinguished as the clavus (Fig. 146, 

Fir,. 146. — Diagram of a front wing of a bug: C l) \ the Other part is the COrium (Fig. 
d, clavus; co, cerium; *, membrane. ^ ^ The terminal portion of the 

front wing is termed the membrane (Fig. 146, m). In certain families, 
the Anthocoridae for example, a narrow piece along the costal margin of the 
wing is separated by a suture from the remainder of the corium; this is the 
embolium (Fig. 149, e). In certain other cases, as the Miridas for example, a 
* Hemiptera: hemi- (17/u). half; pteron (irrepov), a wing. 
94 


HEMIPTERA 


95 


triangular portion of the terminal part of the corium is separated as a dis- 
tinct piece; this is the cuneus (Fig. 148, cu). 

The mouth-parts are formed for piercing and sucking. Without 
dissection, they usually appear as a slender segmented beak arising from 
the front part of the head (Fig. 149). The beak consists of the labium 


Fig. 147. — Diagram of a front wing of an antho- 
corid: e, embolium. 


Diagram of a front wing of a mirid: 


Fig. i4g. — Head of Lethocerus: c, clypeus; /, la- 
brum; Ip, labial palpi; y, y, maxillary sclerites. 


with possibly vestiges of the labial palpi combined with it. The beak is 
deeply grooved on the dorsal surface forming a channel in which are four 
long, slender setae or bristles, two of which are the much 
modified mandibles and two the greatly changed maxilla?. 
The beak is not a piercing organ; its function is to protect 
and direct the seta? and to determine, by means of tactile 
hairs at its tip, the place where the puncture should be made 
by the setae (Fig. 150). 

The mandibular and maxillary setae when in use, are 
pushed beyond the tip of the beak in order to pierce the 
tissues of the plant on which the insect is feeding. 

Most of the Hemiptera protect themselves by the emis- 
sion of a fluid having a disagreeable odor. In the stink- 
bugs, PentatomidcB, the fluid is excreted through two 
openings on the ventral side of the thorax near the middle 
coxae. In the bedbugs the openings are in the dorsal wall of FlG lso _ Mouth . 
the first three abdominal segments. p arts of Bu e- ( After 

In the Hemiptera the metamorphosis is incomplete ; the 
newly-hatched young resembles the adult in the form of its body but lacks 
wings. After one or two molts the wing-buds appear and become 
larger and larger at successive molts. With the last molt there takes 
place a great expansion of the wings, the change at this time being much 
greater than at either of the previous molts. There are many wingless 
forms in this order. In some species all individuals are wingless; in 
others there are two forms of adults, the winged and the wingless. 


9 6 THE STUDY OF INSECTS 

TABLE FOR DETERMINING THE FAMILIES OF THE HEMIPTERA 

A. Antennae shorter than the head, and nearly or quite concealed in a cavity beneath 
the eyes. 

B. Hind tarsi with indistinct setiform claws (except in Plea, of the family No- 
tonecitidae, which are less than 3 mm. in length). 
C. Fore tarsi consisting of one segment, which is flattened or shovel-shaped, and 

without claws; head overlapping the prothorax dorsally. p. 97. . . .CORlxiDiE 
CC. Fore tarsi of the usual form, and with two claws; head inserted in the 

prothorax. p. 98 Notonectid^e 

BB. Hind-tarsi with distinct claws. 

C. Caudal end of the abdomen furnished with a respiratory tube composed of a 
pair of grooved, thread-like organs; tarsi one-segmented, p. 98. . . .Nepid.e 
CC. Caudal end of abdomen without long respiratory tube. 

D. Legs flattened, fitted for swimming; caudal end of the abdomen furnished 
with a pair of strap-like appendages (these appendages are retractile and 
are frequently withdrawn from sight) ; tarsi two-segmented, p. 99 

BELOSTOMATID/E 

DD. Legs fitted for walking; abdomen without strap-like caudal appendages. 

E. Without ocelli, p. 107 Kaucorid/e 

EE. Ocelli present, p. 100 Gelastocorid/E 

AA. Antennae at least as long as the head, usually free, rarely (Phymatidce) fitting in 
a groove under the lateral margin of the pronotum. 
B. Body linear; head as long as the three thoracic segments, p. 107 

HYDROMETRID/E 

BB. Body of various forms, but, when linear, with the head shorter than the 

thorax. 

C. Last segment of the tarsi more or less split, and with the claws of at least 

the front tarsi inserted before the apex. 

D. Hind femora extending much beyond the apex of the abdomen; the 

middle and hind pairs of legs near together and very distant from the 

front pair; beak four-jointed, p. 101 Gerrid.e 

DD. Hind femora not extending much beyond the apex of the abdomen; 
middle pair of legs about equidistant from front and hind pairs (except in 

Rhagovelia); beak three-jointed, p. 101 Veliid^e 

CC. Last segment of the tarsi entire, and with the claws inserted at the apex. 
D. Antennae four-jointed.* 

E. Hemelytra resembling network, and very rarely with any distinction 

between the corium and the membrane, p. 104 Tingid/E 

EE. Hemelytra of various forms or absent, but not of the form presented 
by the Tingidae. 

F. Beak three-jointed. 

G. Hemelytra when well developed with an embolium (Fig. 147); those 

forms in which the adult has vestigial hemelytra have no ocelli. 

H. Hemelytra vestigial; parasitic bugs preying on man, bats, and 

birds, p. 102 Cimicid.^ 

HH. Hemelytra usually well developed; not parasitic bugs. p. 102 

Anthocorid^e 

GG. Hemelytra when well developed without an embolium; those 
forms in which the adult has vestigial hemelytra have ocelli. 
H. Ocelli wanting. 

I. Body greatly flattened, p. 108 Aradid.e 

II. Body not greatly flattened, p. 103 Reduvud/E 

HH. Ocelli present, though sometimes difficult to see. 

I. Beak long, reaching to or beyond the intermediate coxae; an- 

tennae not whip-like; membrane of hemelytra with looped 
veins, p. 100 . . Saldid/E 

II. Beak not reaching the intermediate coxae. 

J. Front legs with greatly thickened femora, p. 104. .PHSTMATHME 

JJ. Front femora somewhat thickened, but much less than half 

as wide as long. p. 103 Reduviid^e 

* In some cases there are minute intermediate joints between the principal joints 
of the antennae; for the purposes of this table these intermediate joints are not counted. 


HEMIPTERA 97 

FF. Beak four-jointed. 

G. Front legs fitted for grasping prey, the tibiae being armed with 
spines and capable of being closed tightly upon the femora, which 
are stout. In the forms with long wings the membrane is usually 
furnished with four long veins, bounding three discal cells which are 
often open. From these cells diverge veins which form several 

marginal cells (Fig. 165). p. 103 Nabid^e 

GG. Front legs fitted for walking. 

H. Hemelytra with cuneus; membrane with one or two closed cells 

at its base; tarsi furnished with an arolium. p. 101 . . . . Mirid^e 

HH. Hemelytra without cuneus. Membrane with four or five simple 

or anastomosing veins arising from the base; or with a large 

number of veins arising from a cross-vein at the base. 

I. Ocelli wanting. 

J. Exceedingly flat bugs. p. 108 Aradid^e 

JJ. Rather stout and heavily formed bugs. p. 104 

PYRRHOCORID/E 

II. Ocelli usually present. 

J. Head with a transverse incision in front of the ocelli, which 

are always present, p. 107 Neidid.e 

JJ. Head without transverse incision. 

K. Membrane with four or five simple veins arising from 
the base of the membrane, the two inner ones sometimes 

joined to a cell near the base (Fig. 173). p. 105 

LyCEIDjE 

KK. Membrane with many, usually forked veins, springing 
from a transverse basal vein (Fig. 175). p. 106 

COREID/E 

DD. Antennae five-jointed.* 

E. Tibiae armed with strong spines; hemelytra with the clavus markedly 

thicker than the membrane, p. 108 Cydnid^e 

EE. Tibiae smooth or with small spines. 

F. Scutellum narrowed behind, only rarely almost covering the abdomen. 

p. 106 Pentatomid;e 

FF. Scutellum not narrowed as in the Pentatomidae, very convex, nearly 
or quite covering the abdomen, p. 108 Scutellerid^e 

* In some cases there are minute intermediate joints between the principal joints 
of the antennae; for the purposes of this table these intermediate joints are not 
counted. 

Family Corixid^e 

The Water-boatmen 

The family Corixidae includes oval, gray-and-black mottled bugs, 
usually less than half an inch in length, which live in lakes, ponds, and 
streams, in both stagnant and running water. The 
characteristic form and markings of these insects are 
shown in Figure 151. 

The beak is very short, the middle legs are very 
long and slender, and end in two claws, while the hind 
legs are long, flattened and fringed for swimming. The 
water-boatmen have the body flattened on the dorsal 
side and they swim on the ventral side in normal posi- 
tion. 

The body of these insects, as they swim through 
the water, is almost completely enveloped in air, which 
glitters like a silver armor. This air is purified by contact with the fine 
particles of air scattered through the water; so that the insects can breathe 


9 8 THE STUDY OF INSECTS 

their coats of air again and again if they are in clean water. If the insects 
are in stagnant water they have to come to the surface at intervals for a 
fresh supply of air. 

In their favorite attitude the water-boatmen are anchored to some 
object near the bottom of the water by their long middle legs. The body 
of these insects, with the air which clings to it, is much lighter than water; 
consequently whenever they lose hold upon the object to which they have 
been clinging, they rise quickly to the surface, unless they prevent it by 
swimming. They occasionally float on the surface of the water, and can 
leap into the air from the water and take flight. 

These insects feed upon the vegetable matter in the ooze at the bot- 
toms of ponds and at the same time consume the minute animals which 
are present in this plant material. 

Both the adults and eggs of species of the genus Corixa are used as 
food for man and for birds. It is said that in Mexico the natives bind 
the stalks of a sedge into bundles which are then floated on the water of 
a lake where the bugs will deposit their eggs on them in great abundance. 
The bundles are then removed and dried and the eggs beaten off on to a 
cloth and then ground into flour for baking. The adults and eggs of 
Corixa mercendria are said to be imported into England by the ton as 
food for birds, game, and fish. 

Family Notonectid^; 

The Back-swimmers 

The back-swimmers have the back shaped like the bottom of a boat 
instead of being flat like that of the water-boatmen and they differ from 
all other aquatic bugs in that they always swim on their backs. 

The favorite attitude of the back-swimmers is floating on the surface 
of the water, back downward, with the hind end of the body projecting 
sufficiently to admit of air being drawn into two air chambers on the 
ventral side of the body. There are two longitudinal furrows on the 
ventral side of the abdomen arched over by long hairs thus forming two 
tubes into which air is taken. The spiracles open into these tubes. 

The hind legs are long and act as oars and when the back-swimmers 
are disturbed they dart away toward the bottom of the 
pond. They do, however, lie right side up on the sur- 
face of the water occasionally and often take flight into 
the air. 

fig. 152. — a back- The species of the genus, Notonecta, are most com- 
swimmer - mon (Fig. 152). They have sharp piercing mouth-parts 

and sometimes sting with them unless handled carefully. 

Family Nepid^e 

The Water-scorpions 

The water-scorpions have two long filaments on the end of the body, 
which are grooved on the inner side. By putting these filaments together 
a long tube is formed, which the insects can project to the surface of the 
water, and thus obtain air for breathing, while resting on the bottom of 


HEMIPTERA 


99 


the pond. This tube conducts the air to two spiracles at the caudal end 
of the abdomen. 

The most common members of this family- 
belong to the genus Rauatra (Fig. 153). These 
are long, slender bugs with long, slender legs. 
The only other representative of the family 
found in the United States is Nepa apiculata. 
In this species the body is oval, flat, and thin, and 
measures about two-thirds of an inch in length, 
not including the breathing-tube (Fig.. 154). 
s*^ ^ -v^ The water-scorpions live 

^*»w^ g^^ among rubbish or on the stems of 
^~v Jtty-^ water-plants, in ponds and in the 
^f quiet parts of our streams. They 
JSjL Ib^ are carnivorous, and have the 
I ■ H ] first pair of legs fitted for seizing 
/ ^Hr I P ,v . v - ^n these legs the coxa is 
▼ very long, and the femur is fur- 

nished with a groove into which 
I the tibia and tarsus fit like the 

blade of a pocket-knife into the 
epa handle. 

The eggs of these bugs are in- 
serted in the decaying tissues, often stems, of 
aquatic plants. Although these insects are aquatic the second and hind 
pairs of legs are fitted for walking rather than for swimming. 


Fig. 154. 
apiculata. 


Fig. 153. — A water-scorpion. 


Family Belostomatid^; 
The Giant Water-bugs 

The common name "giant water-bugs" was applied to this family 
because it contains the largest of the Hemiptera now living. 

The members of this family are all wide and 
flat-bodied aquatic insects. The fore legs are 
for grasping, the middle and hind legs are 
fitted for swimming. At the caudal end of the 
body there is, in the adult, a pair of narrow, 
strap-like respiratory appendages, which are 
retractile. 

These insects are rapacious creatures, feed- 
ing on other insects, snails, and small fish. Like 
other water-bugs, they fly from pond to pond 
and are frequently attracted to lights. This 
is especially the case where electric lights 
are used, into which they sometimes fly and are 
killed by hundreds. On this account they are 
known in many parts of the country as ' ' electric- 
light bugs." 

Figure 155 represents Lethocerus americanus. 
In Lethocerus, the front femora are grooved 
for the reception of ,the tibia?, as in the pre- fig. 155. — Lethocerus americanus. 


THE STUDY OF INSECTS 


Fie. 156. — Belos- 
toma jluminea. 


Fig. is7 — Eggs on 
back of Abedus. 


ceding family. Another common rep- 
resentative of the family is Bendcus 

griseus. This resembles Lethocems 

americanus very closely but can be 

distinguished from it by the absence 

of the femoral groove. 

There are other smaller species of 

this family which belong to the genus 

Belostoma. Our most common species 

is Belostoma fluminea (Fig. 156). 

In this genus and in Abedus the 

eggs are carried by the males on their 
backs, where they are placed by the females, some- 
times in spite of vigorous opposition on the part of 
the male (Fig. 157). 

Family Gelastocorid^ 

The Toad-shaped Bugs 

The Gelastocoridae was formerly known as the Galgulidas. 
In these insects the body is broad and short, and the eyes are promi- 
nent and projecting; the form of the body and the protuberant eyes 
remind one of a toad (Fig. 158). Ocelli are present. The antennae are 
short and nearly or quite concealed beneath the eyes. The beak is short, 
stout, and four-segmented. The fore legs are raptorial. 

The toad-shaped bugs live on the muddy margins of 
streams or other bodies of water. Some of them make holes 
for themselves, and live for a part of the time beneath 
the ground. They feed upon other insects, which they cap- 
ture by leaping suddenly upon them. Their colors are pro- 
Fig. 158. — Gdas- tective and vary so as to agree with the color of the soil 

tocaris oculalus. Qn ^^ they ^ The ^ ^ buried ^ the ^d. 

The most common and most widely distributed representative of the 
family found in this country is Gelastocoris oculatus (Fig. 149). 


Family Saldid/E 

The Shore-bugs 

These are certain small bugs, of dark colors with white or yellow 
markings, which abound in the vicinity of streams and 
lakes, and upon damp soils, especially of marshes near our 
coasts. The shape of these shore-bugs is shown by Figure 
159. The antennas are long and conspicuous. The beak is 

three-segmented and very long. shore^u! 9 " ~~ A 

Some of the shore-bugs dig burrows, and live for a part of the 
time beneath the ground. They take flight quickly when _ disturbed, but 
alight after flying a short distance, taking care also to slip quickly into 
the shade of some projecting tuft of grass or clod where the soil agrees 
with the color of their bodies. 

Thirty-three species belonging to this family have been found in the 
United States and Canada; these represent eight genera. 


HEMIPTERA 101 

Family Veliid^; 
The Broad-shouldered Water-striders 

The Veliidae includes insects which are closely related to the water- 
striders of the next family. The bodies of these insects are usually 
stout, oval and broadest across the prothorax. The legs 
are not extremely long and the second pair is about 
equidistant from the front and hind pairs except in the 
genus Rhagovelia (Fig. 160). 

The broad-shouldered water-striders are found both 
on the banks of streams and ponds and on the surface of 
the water. The small, plump-bodied species of Micro- Fig. 160. — Rhago- 
velia are found at the water's edge but run out on the 
water when disturbed. Those of Rhagovelia which arc larger, run on the 
surface of rapid streams. 

These water bugs are dimorphic, for both fully winged and short- 
winged to wingless adults occur in the same species. 

Family Gerrid^e 

The Water-striders 

On the quiet pools of streams or calm waters of ponds one may 
usually find numbers of rather long-bodied insects with long slender legs, 

skimming about over the surface of the 
water. These are the true water-striders. 
The long middle and hind legs are near 
together and distant from the front legs 
(Fig. 161). It should be noted that some 
water-striders have comparatively short 
oval bodies. 

These insects are predacious and feed 

on other insects which happen to fall in 

fig. 161. - a water-strider. t j ie . wa t er ; they of ten jump from the water 

to capture flies. In the fall, the water-striders hide away beneath the banks 

of the streams or at the bottoms of the pools and there they remain until 

spring. 

There are commonly winged and wingless forms of the same species. 
Thus these insects are dimorphic. 

Twenty species of water-striders are known from our fauna and those 
of the genus, Halobates, are deep sea forms for they live on the surface 
of the ocean, often hundreds of miles from land. 

Family Miridve 

The Leaf-bugs 

This family, formerly known as the Capsidas, is the largest family of 
the Hemiptera. The species are small or of medium size but they vary 
greatly in form and markings. The hemelytra are rather characteristic 


io2 THE STUDY OF INSECTS 

for they are nearly always complete with clavus, corium, cuneus and 
membrane. The family contains several well-known economic forms. 

The four-lined leaf-bug, Pcecilocapsus linedtus, is a bright, 
yellow bug about § of an inch long, with four longitudinal 
black lines along its back (Fig. 162). It attacks various 
plants but is most injurious to currants, gooseberries, deutzia, 
dahlia, and weigelia. Its eggs are laid in groups of 6 to 8 in 
the stems of the food plants. There is one generation each 
fig. 162. — Poecii- year. 
ocapsus hmatus. /pj^ Garnished plant bug, Lygus pratensis, is a greenish to 

dull brown bug about -5- of an inch long with a V-shaped yellowish mark on 
the scutellum. It has been recorded on about fifty different plants and is 
often seriously injurious to asters, dahlias, and celery and to apple and 
peach trees in the nursery row. No satisfactory method of control is 
yet known. 

The apple redbug, Lygidea mendax, is another injurious species of this 
family. The nymphs are bright red in color but the adults are lighter 
and not so conspicuous. Both the nymphs and adults puncture the 
young apples with their beaks, thereby causing the fruit to become knotty, 
deformed and misshapen. The bugs can be controlled by spraying the 
trees after the petals have fallen with nicotine-sulphate at the rate of 
f of a pint to 100 gallons of water. 

Family Anthocorid^e 

The Flower-bugs 

The flower-bugs are small insects living on flowers, often on trees 
and sometimes under bark or rubbish. They are predacious and happily 
some of them prey upon injurious species of insects. The most common 
one is the insidious flower-bug, Triphleps insidiosus, which is black and 
only about ^ of an inch in length. It is common on flowers as well as 
in other situations. It preys on Phylloxera on the leaves of grapes and 
sometimes on the chinch-bug. 

Family CimicidjB 

The Bedbug Family 

The members of this family are parasitic bugs, which are either wing- 
less or possess only vestigial hemelytra. In these insects the ocelli are 
absent, the antennas are four-jointed, the beak is three-jointed, and the 
tarsi are three-jointed. Only four species belonging to this family have 
been found in America north of Mexico. These are the bat bedbug, 
Clmex pilosellns , which is parasitic on the bat, the species found in the 
nests of swallows, CEciacus vicarius, the species which infests poultry in 
the Southwest, Hamatoslphon inodorous, and the common 
bedbug, Clmex lectuldrius, which sometimes attacks poultry 
as well as man. The bedbug is a well-known pest over the 
greater part of the world. It is reddish brown in color, and 
measures when full-grown from one-sixth to one-fifth inch 
in length. The body is ovate in outline and very flat (Fig. 
1 63). It is wingless, or has very short vestigial hemelytra. 


HEMIPTERA 


103 


The begbug is nocturnal in habits, hiding by day in the cracks of 
furniture and beneath various objects. The white oval eggs are laid in 
batches in cracks and crevices of bedsteads and furniture, under seams of 
mattresses and in other places. They hatch in from six to ten days and 
the nymphs, under favorable conditions, become grown in 35 to 48 days. 
In well-heated houses the bugs will multiply all the year round. 


Family Nabid^e 
The Nabids 


and somewhat oval behind. In 
short-winged and a long-winged 


Fig. 164. — Nabis 
subcoleoptratus. 


Fig. 165. — Hemelytron of Nabis ferus. 


In this family the body is oblong 

some species there are two forms, a 
form. In case of one of 
the most common spe- 
cies, Nabis subcoleop- 
tratus, the short-winged 
form (Fig. 164), in 
which the hemelytra 
barely reach to the 
second abdominal segment, is much more abundant than 

the long-winged form. It is of a shining jet-black color with yellowish 

legs. 

Family Reduviid^; 
The Assassin-bugs 

This is a large family containing bugs of very diverse form. They 
are predacious on other insects and sometimes on the higher animals, 
even attacking man. The beak is three-segmented and very efficient as a 
puncturing instrument. 

The masked bedbug hunter, Reduvius personatus, has become noto- 
rious as a "kissing bug" for it often inflicts painful wounds on the cheeks 
and lips of human beings with its beak. The nymphs of this bug are 
masked with lint and dust which adhere to the body by reason of a 
sticky substance secreted by the insect. These nymphs frequent houses 
and often destroy bedbugs when the latter can be found. The adult 
(Fig. 166) is very dark brown and about § of an inch in length. 
The big bedbug, 
Triatoma sanguisilga, 
which occurs in the 
southern states is nearly 
an inch long. It attacks 
man as well as chickens 
and sucks the blood. 

The wheel -bug, Ari- 
lus cristatus, is of inter- 
Redu- est because of the 
cogwheel-like crest on 
See page 108. w 
The thread-legged bug, Emesa brevipennis, is a curious form with its 
long, slender body and thread-like legs (Fig. 167). 


Fig. 166.— 

vius personatus 


its prothorax. 


Fig. 167. — Emesa brevipennis. 


io4 


THE STUDY OF INSECTS 


Family Phymatid^ 

The Ambush-bugs 

The ambush-bugs are notable for the form of the front legs which are 
modified into grasping organs. The antennae are also notable because 
the terminal segment of each is more or less enlarged into a knob-like 
form. 

The most common member of this family is Phymata erosa 
(Fig. 1 68). It is a greenish insect, with a black band across 
the broadly expanded abdomen. It conceals itself in flowers, 
fig. i 68.— and captures the insects which come to sip nectar. It is es- 
Phymata erosa. p ec j a iiy abundant among the flowers of golden-rod. It over- 
powers and captures insects like cabbage butterflies, honey-bees and large 
wasps. 


Family Tingid^; 

The Lace-bugs 

The Tingida? are doubtless the most easily recognized of all Hemip- 
tera. The lace-like structure of the hemelytra, usually accompanied by 
expansions of the prothorax of a similar structure, gives these insects a 
characteristic appearance which 
needs only to be once seen to be 
recognized in the future (Fig. 169 
and 170). They are generally very 
small insects. But they occur in 
great numbers on the leaves of 
trees and shrubs, which they 
puncture in order to suck their 
nourishment from them. 'Their 
eggs are fastened to leaves, and 
covered by a brown, sticky sub- 
stance ; they appear more like fungi 
than like the eggs of other insects. 


Fig. i6q. — A tingid, Cory 
/'mi ha iircuala. 


Fig. 170. — Eggs and 
nymph of the tingid, C 
arcuata. 


Family Pyrrhocorid^ 
The Cotton-stainer Family 

The members of this family are rather stout and heavily formed 
bugs, and are generally black or brown, marked with red. In this family 
there are two or three large cells at the base of the membrane, and from 
these arise branching veins (Fig. 171). 

The most important member of this family is the cotton-stainer, 
Dysdercus suturellus, which is about § of an inch long (Fig. 172). 
The head, front part of thorax, and underside of the abdomen are red 
while the dark brown hemelytra are marked with light yellow lines. The 
nymphs are red. The insect punctures the immature bolls and the seeds 
within. The seeds exude a material which stains the lint an indelible 


HEMIPTERA 


105 


yellowish color. The colonies of red nymphs may be brushed off into pans 
of kerosene or the bugs may be trapped in the fall under and on heaps 
of cotton seeds placed here and there in the field and then destroyed. 

The bordered plant-bug, Enryophthal- 
rnus succinctus, is probably the most widely 
distributed species of this family. It is 
found from New Jersey to Mexico. It is 
brownish-black with the sides of the pro- 
thorax margined with orange or red. It has, 
under certain conditions, become injurious 
to cotton. 


Fig. 171. — Hemelytron of Euryophthalmus suc- 
cinctus. 


Fig. 172. — Dysdercus su- 

lurellus. 


Family Lyg.^eid^ 
The Chinch-bug Family 

This, too, is a large family, about two hundred species being known to 
occur in the United States. Here the membrane of the wing-covers is 
furnished with four or five simple 
veins, which arise from the base of 
the membrane; sometimes the two 
inner veins are joined to a cell near 
the base (Fig. 173). 

This family contains the chinch- 
bug, BllSSUS leucopterus, the most FiG.173— Hemelytron of Ly S *«s. 

destructive member of the family occurring in the United States. Al- 
though quite widely distributed, its injuries have attracted 
most attention in the Mississippi Valley, where it has de- 
stroyed many million dollars' worth of grain. It is a small 
bug, measuring less than one-sixth of an inch in length. 
It is blackish in color, with snowy-white wing-covers, each 
marked with a dark spot and Y-shaped line, as shown in 
the Figure 174. The species is dimorphic, there being a 
short-winged form. 

There are two generations of the chinch-bug each year; they winter 
as full-grown insects and hide in stools of grasses. In the early spring 
they come forth and lay their eggs in fields of grain upon the roots or 
stems beneath the ground. The eggs hatch in about two weeks. The 
nymphs are red, and feed at first upon roots; afterwards they attack the 
stalks of the plants they infest. In about 45 days they get their growth. 
About this time the whole brood starts out to find new pastures, and 
they all march on foot in one direction, like an army. Although they are 
tiny insects they number millions, and so attract much attention. As 
soon as they find a new field of grain they lay their eggs for another brood. 


io6 


THE STUDY OF INSECTS 


Family Coreid^e 

The Squash-bug Family 

This family is also a very extensive one, including many species of 
various forms. They may be distinguished by the venation of the 
membrane of the hemelytra. This part is furnished with many veins, 

most of which spring 
from a cross-vein near its 
base (Fig. 175). 

The squash-bug, An- 
asa tristis, is a good 
example of this great 
family. These when full- 
grown are brownish-black bugs, with some yellow spots along 
the edges of the abdomen (Fig. 176), and are dirty yellow on 
the under side. This bug winters in the adult state, and takes the first 
opportunity in the spring to lay its eggs on the leaves of squash and 
pumpkin vines. As soon as they hatch, the young bugs attack the vines 
and are apt to destroy them entirely. 


FlG. 175. — Hemelytron of Leptocoris Irivillalus. 


Fig. 176. — Anasa 
iristis. 


Family Pentatomid^e 

The Stink-bug Family 

This is a family the taste and odor of which most of us know to our 
sorrow. We learn the flavor in one experience, and conclude that once is 
enough for a lifetime. 

It should not be concluded, however, that only members of this 
family possess this disagreeable odor; for most of the Hemiptera protect 
themselves by rendering their bodies unpalatable in this way. 

This nauseous odor is caused by a fluid which is excreted through 
two openings, one on each side of the under side of the body near the 
middle coxas. 

In this family the antennae are five-jointed; the scutel- 
lum, although large, is usually less than half as long as the 
abdomen (Fig. 177). 

Some species of this family feed upon other insects, and 
so are very helpful to the farmer, one species especially 
{Perillus bioculatus) being a gallant fighter against the 
potato-beetle. Other species feed entirely upon vegeta- 
fig. 177— a bles, while others live upon both vegetable and animal 

pentatomid. matter . 

The harlequin cabbage-bug or calico-back, Murgdntia histrionica, 
is very destructive to cabbages, radishes, and turnips in the southern 
states and on the Pacific coast. It is black with bands, stripes, and 
margins of red or orange or yellow. The full-grown bugs live through 
the winter, and in the early spring each female lays on the under surface 
of the young leaves about twelve eggs in two parallel rows. The young 
bugs are pale green, with black spots. They mature in a few days, so 
there are many generations in one season. 


HEMIPTERA 


107 


Other Families of the Hemiptera 

For a more detailed discussion of the following families the student is 
referred to "An Introduction to Entomology" by J. H. Comstock. 

Family Naucoridce. The creeping water-bugs are flat-bodied mod- 
erate-sized insects living in water. The front legs are fitted for grasping 
and the insects live among reedy or grassy, quiet waters where they creep 
about among the plants. There are only two genera in our fauna, Pelo- 
coris and Ambry sus, with but a few species. 

Family Ochteridce. These are shore-inhabiting bugs with only a few 
species in the United States, all of the genus Ochterus. 

Family Mesoveliidce. There are only two species of this family known 
in our fauna. Both are small insects less than one-fourth of an inch in 
length. One, at least, lives on the surface of the water in quiet ponds. 
Family Hebrides. This is a family of small plump-bodied bugs meas- 
uring less than one-eighth of an inch in length. There are two genera, 
Hebrus and Merragdta, containing but six species in our fauna at the 
present time. 

Family Hydrometridce. At least three species of these long, narrow- 
bodied insects with long, slender legs and antennae occur 
in the United States (Fig. 178). They creep slowly upon 
the surface of the water in quiet weedy places. 

Family Schizopteridce. But a single species of this 
family has yet been found in the United States. This 
one is only about -jV of an inch in length. It lives among 
fallen leaves, rubbish, and earth. 

Family Dipsocorida. There are only two or three 
species of this family and they are all small, less than 
1*2 of an inch in length. 

Family Isometopidce. Two species of this family 
have been found in the Southwest and two in the East. 
Both of the eastern forms are rare and all of them are 
small measuring not more than -^ of an inch in length. 

Family Termatophylidce. This family, although small 
in number, is world wide in distribution. One species 

has been found in the United States, but only 
the female of this one has been described. 

Family Polyctenidce. The many-combed bugs 
are rare but are of interest because they are 
parasitic on bats. One species, Hesperoctenes 
longiceps, has been described from a bat in 
southern California. The hemelytra are vestigial. 
Family Enicocephalidce. These are called 
the unique-headed bugs because the head 
differs in form from all other Hemiptera. Ap- 
parently but two species have been found up 
to this time in the United States. 

Family Neididce. The Neididae, known as 

stilt-bugs, are striking in appearance because 

the body is long and narrow and is furnished 

fig. no. — jaiysmspinosus. with long slender antennae and legs (Fig. 179). 


Fig. 178. — Hydrometra. 


io8 


THE STUDY OF INSECTS 


Of the few species in our country but two are widely distributed. These 
are sluggish insects found in the undergrowth of woods and in meadows 
and pastures. The most common representative is J&lysus spindsus which 
is widely distributed in the United States and Canada. It has been found 
to be a serious pest of tomatoes in some localities for it punctures the stems 
and fruit and sucks out the juices. 

Family Aradidcs. The members of this family are known as the flat- 
bugs because their bodies are very flat and thin. They live in the cracks 
or beneath the bark of dead trees and logs. They are usually brownish 
to black and the hemelytra are reduced in size. Some of them somewhat 
resemble bedbugs and because of this there was an old idea prevalent in 
the days of log houses that bedbugs got into the house from the logs used 
in constructing it. There are several genera in this family and at least 
fifty-nine species are known in this country. 

Family Cydnidce. This family includes two fairly well defined groups 
of bugs, the burrower-bugs and the negro-bugs. Of the first group the 
species are generally black or very dark brown and they 
burrow in sandy places or beneath sticks or stones or at the 
roots of grasses. 

The negro-bugs are short, broad, and very convex. 
They are mostly black and beetle-like in appearance. They 
infest various plants. There are only a few species. 

Family Scutelleridce. These are known as the shield- 
backed bugs because the scutellum covers nearly the 
whole of the abdomen. The body is short, broad, and 
convex (Fig. 180). 


Fro. 

shield-backed bu; 


Fig. 180a. — The wheel-bug, Arilus cristatus (From Glover). See page 103. 


CHAPTER XVIII 
ORDER HOMOPTERA* 


Cicadas, Leaf hoppers, Apkids, Scale-bugs, and others 

The winged members of this order have four wings, except in the family 
Coccidce; the wings are of the same thickness throughout, and usually are 
held sloping at the sides of the body when at rest. The mouth-parts arc 
formed for piercing and sucking; the beak arises from the hind part of the 
lower side of the head. The metamorphosis is incomplete except in some highly 
specialized forms. 

Although the Homoptera is a well-defined order, the families of which 
it is composed differ greatly in the appearance of their members. For 
this reason there is no popular name that is applied to the order as a 
whole. 

The wings of the Homoptera are usually membranous, but in some 
the front wings are subcoriaceous. In these cases, however, they are of 
quite uniform texture throughout, and not thickened at the base as in the 
Hemiptera. 

Many wingless forms exist in this order; in the family Coccidas the 
females are always wingless; and in the family Aphididas the males may 
be either winged or wingless, while usually the sexually perfect females 
and certain generations of the agamic 
females are wingless. In the Coccidce 
the males have only a single pair of 
wings, the hind wings being represented 
by a pair of club-like hal teres. 

In the Homoptera the front part of 
the head is bent under and back so that 
the beak arises from the hind part of the 
lower side of the head. 

The mouth-parts are formed for 
piercing and sucking. The piercing 
organs consist of four long, bristle-like 
setae, the mandibular and maxillary 
setas; these are enclosed in a long, 
jointed sheath, which is the labium. 
The labium and the enclosed setas con- 
stitute what is commonly termed the 
beak. 

As an example of the homopterous ««• maxill] ,7 f , seta A ; , c \ c \ y t pe ^ l \ labi T, ; ,'A epi ; 

... * r pharynx. (After Marlatt with changed lettering.) 

type ot head and mouth-parts those of a 

cicada are probably the most available, on account of the large size of these 
insects and the comparative ease with which the parts of the head can be 
distinguished. Figure 181 represents a front view of the head. 
* HomSptera: homos (6/j.os), same, pteron (irrepop), a wing. 

IOQ 


Fir,. 181. — Head of cicada: mi. rmndibularseta; 


no THE STUDY OF INSECTS 

TABLE FOR DETERMINING THE FAMILIES OF THE HOMOPTERA 

A. Beak evidently arising from the head; tarsi three-jointed; antennae minute, 
bristle-like. 
B. With three ocelli, and the males with musical organs. Usually large insects, 

with .-ill the wings entirely membranous, p. i 10 Cicadid/E 

BB. ( kvlli only two in number or wanting; males without musical organs. 

C. Antennae inserted on the sides of the cheeks beneath the eyes. p. 113 

Fulgorid^e 

CC. Antenna' inserted in front of and between the eyes. 
I '. 1'rothorax not prolonged above the abdomen. 
E. Hind tibiae armed with one or two stout teeth, and the tip crowned with 

short, stout spines, p. 1 1 1 Cercopid^e 

EE. Hind tibiae having a row of spines below, p. 112 CicadelliDjE 

DD. Prothorax prolonged into a horn or point above the abdomen, p. 112 

Mkmbracid/e 

AA. Beak apparently arising from between the front legs, or absent; tarsi one- or 
two-jointed; antennae usually prominent and threadlike, sometimes wanting. 
B. Tarsi usually two-jointed; wings when present four in number. 
C. Wings transparent. 

D. Hind legs fitted for leaping; antennae nine- or ten-jointed, p. 114 

Chermid.e 

DD. Legs long and slender, not fitted for leaping; antennae three- to seven- 
jointed, p. 114 and 118 Aphidid^e and Phylloxerid.e 

CC. Wings opaque, whitish; wings and body covered with a whitish 

powder, p. 1 18 Aleyrodioe 

BB. Tarsi usually one-jointed; adult male without any beak, and with only 
two wjfigs; female wingless, with the body either scale-like or gall-like in 
form, or grub-like and clothed with wax. The waxy covering may be in the 
form of powder, of large tufts or plates, of a continuous layer, or of a thin 
scale beneath which the insect lives, p. 119 Coccid^e 

Family Cicadid^e 

The Cicadas 

The large size and well-known songs of the more common species of 
this family render them familiar objects. It is only necessary to refer to 
the periodical cicada and to the harvest-flies, one of which is represented 
by Figure 182, to give an idea of the more striking 
characteristics of this family. 

The species are generally of large size, with a 
subcorneal body. The head is wide and blunt, with 
prominent eyes on the outer angles, and three bead- 
like ocelli arranged in a triangle between the eyes. 
They are notable for the complex musical organs of 
of the males with which they produce their so-called 
song, a loud, sustained, usually high-pitched noise 
emitted during the warm days of summer. There 
are over seventy species of cicadas in our fauna. 

They are several species of cicadas that are 
commonly known as dog-day cicadas or harvest-flies ; 
a common one of these is the species that has re- 
ceived the popular name of the lyreman; this is 
Tibicen linnet (Fig. 182). The shrill crv of this 

Fig. ito.-TMcenlmnei. spccies> wWch ig the most prominent of the various 

insect sounds heard during the latter part of the summer, has made its 
author familiar to many. This insect varies both in size and colors. It 


HOMOPTERA in 

commonly measures two inches to the tip of the closed wings; it is black 
and green, and more or less powdered with white beneath. 

The member of this family that has attracted most attention is the 
periodical cicada, Magicicada septcndecim. This species is commonly 
known as the seventeen-year locust; but the term locust when applied 
to this insect is a misnomer, the true locusts being members of the order 
Orthoptera. This species is remarkable for the long time required for it 
to attain its maturity. The eggs are laid in the twigs of various trees 
by the female. Sometimes this cicada occurs in such great numbers that 
they seriously injure small fruit trees, by ovipositing in the twigs and 
smaller branches. The nymphs hatch in about six weeks. They soon 
voluntarily drop to the ground, where they bury themselves. Here they 
obtain nourishment by sucking the juices from the roots of forest and 
fruit trees. And here they remain till the spring of the seventeenth year 
following. They emerge from the ground during the last half of May, at 
which time the empty pupa-skins may be found in great numbers, cling- 
ing to the bark of trees and other objects. It is at this period that the 
cicadas attract attention by the shrill cries of the males. The insects 
soon pair, the females oviposit, and all disappear in a few weeks. 

Seventeen distinct broods of this species have been traced out; so 
that one or more broods appear somewhere in the United States nearly 
every year. In many localities, several broods co-exist, each brood 
appearing in distinct years. There is a race of the species in which the 
period of development is only thirteen years. This variety is chiefly a 
southern form, while the seventeen-year broods occur in the more north- 
ern states. 

Family Cercopid^e 
The Spittle-insects or Frog-hoppers 

During the summer months one often finds upon various shrubs, 
grass, and other herbs, masses of white froth. In the midst of each of 
these masses there lives a young insect, a member of this family. In 
some cases as many as four or five insects inhabit the same mass of froth. 
It is asserted that these insects undergo all their transformations within 
this mass; that when one is about to molt for the last time, a clear 
space is formed about its body and the superficial part of the froth dries, 
so as to form a vaulted roof to a closed chamber within which the last 
molt is made. 

The adult insects wander about on herbage, shrubs, and trees. They 
have the power of leaping. The name frog-hoppers has doubtless grown 
out of the fact that formerly the froth was called "frog-spittle" and was 
supposed to have been voided by tree-frogs from their mouths. The 
name is not, however, inappropriate, for the broad and depressed form 
of our more common species is somewhat like that of a frog. 

Most of the froth of spittle insects is voided from the anus but a 
mucilaginous material excreted by large hypodermal glands on the 
seventh and eighth abdominal segments is added to the mass which 
renders it viscous and helps to retain the air bubbles introduced into it 
by the insect. The froth is evidently a means of protection. 

In this family the antennae are inserted in front of and between the 
eyes; the prothorax is not prolonged over the abdomen, as in the Mem- 


THE STUDY OF INSECTS 


bracida? ; 


Fig. 183. - 
Lepyronia quad 
rangularis. 


the tibiae are armed with one or two stout teeth, and the tip is 
crowned with short, stout spines, as shown in Figure 183. 

One of the more common and very widely distributed 
species is Lepyronia quadrangular is (Fig. 183). The adult 

of this species is a brownish insect, densely covered with 
microscopic hairs, and black beneath; the hemelytra are 
marked with two oblique brown bands. 


Family Membracid^e 

The Tree-hoppers 

In the tree-hoppers, the prothorax extends backward like a roof over the 
body, often quite covering it. In some cases the prothorax is 
elevated above the head, so that it looks like a horn (Fig. 184) ; 
in others it is shaped like a tam-o'-shanter; and sometimes 
it has horns, one on each side, which have given one species fig. is 4 . — .En- 
the name of the buffalo tree-hopper. chenopa binotata. 

Many species of this family live upon bushes or small trees, and all 
are good leapers; hence the common name, tree-hoppers. Some species 

excrete honey-dew, and are attended by ants. 
All feed upon plants, but they seldom appear 
in sufficient numbers to do much damage. 
Sometimes the females of the buffalo tree- 
hopper, Ceresa bubalus, injure apple trees by 
laying their eggs in large numbers in the 
bark of the smaller branches (Fig. 185). 
The tree-hoppers of the genus, Telamona, have a hump-backed ap- 
pearance (Fig. 186). In many of the tree-hoppers, the eyes have a keen, 


Fie. 185.— 
Ceresa bubalus. 


iS6.— Tcla- 


Fig. 187. — Tree-hoppers. 


droll look, and the line that separates the head from the prothorax 
gives them the appearance of wearing glasses (Fig. 187). 


Family Cicadellid^e 

The Leaf hoppers 

The most abundant members of the Homoptera, except perhaps the 
aphids, are the leafhoppers. Large numbers of them can be easily col- 
lected by sweeping grass, herbage, or the foliage of shrubs. 


HOMOPTERA 


113 


The leafhoppers are slender, small insects, distinguished by the form 
of the hind tibiae, which are nearly or quite as long as the abdomen, 
curved, and armed with a row of spines on each margin (Fig. 
188). 

Among the leafhoppers that have attracted attention on 
account of their injuries to vegetation are the following: the 
destructive leafhopper, Euscelis exitiosus, which is represented 
greatly enlarged by Figure 189, sometimes infests 
grains to a serious extent. The grape-vine leaf- 
hopper, Erythroneura comes, is a well-known pest 
that infests the leaves of the grape. It is about i4 J 
one-eighth inch in length with varied markings fig. i8q — 
of yellow and red on its back. Eleven varieties Eu ^ dis cxlti 
of this one species have been described. The rose 
leafhopper, Empoa rosce, is also a well-known pest, as it often swarms 
on the leaves of roses, doing great damage. Its presence is usually in- 
dicated by numerous white cast skins adhering to the lower side of the 
leaves. The potato leafhopper, Empoasca fabcr, is one of the chief pests 
of the potato. In addition to injuring the plants, it disseminates a disease 
of the foliage known as "hopperburn." The adults are about | of an inch 
long and of a pale yellowish-green color. 


Fig. 188. — On 
comctopia undata 


Family Fulgorid^e 

The Lantern-fly Family 

This family is remarkable for certain exotic forms which it contains. 
Chief among these is the great lantern-fly of Brazil. Scarcely less strange 
are the candle-flies of China and the East Indies. The popular names of 
these insects refer to the fact that they were thought to be phosphorescent, 
but we know of no native species that possesses this peculiarity. There 
does not seem to be any typical form of the body characteristic of this 
family. The different genera differ so greatly, that on superficial exami- 
nation they appear to have- very little in common. Some even resemble 
butterflies and moths, while others might easily be mistaken for neuropter- 
ous genera. 

The most useful character for recognizing these insects is the form 
and position of the antennae. These have two large basal segments and a 
bristle-like terminal portion. They are situated on the side of the cheek 
beneath the eyes. Although the Fulgoridae are vegetable feeders, none 
of our species has attracted the attention of agriculturists. There are, 
however, certain exotic species which do great injury to crops. 
The two accompanying fig- 
ures will serve to show the 
wonderful variations in form of 
these insects ; many other types 
exist. Figure 190 represents a 
common species of Scolops, 
which occurs in grassy places, fig. 191.- 
In this genus the head is greatly prolonged, as with tnonalis - 
the exotic candle-flies. Figure rgi represents Ormenis septentrionalis , a 
beautiful pale-green species powdered with white, which feeds on wild 


Fig. 190. — Scolops. 


■ Ormenis seplen- 


ii 4 THE STUDY OF INSECTS 

grape-vines, drawing nourishment from the tender shoots and midribs of 
the leaves during its young stages. 

Family Chermid^e 

The Jumping Plant-lice 

The jumping plant-lice are comparatively small insects; our more 
common species measuring only from one-twelfth to one-sixth inch in 
length, and it is rare that we find any twice that size. 
When examined with a lens they appear like tiny cicadas 
(Fig. 192). Their hind legs are formed for jumping; their 
antennae are ten-jointed or rarely nine- or eleven-jointed. 
They are very active creatures, jumping and taking flight 
when disturbed. 

The Chermidse subsist entirely upon the juices of 
plants, and some of them cause serious injuries. Many 
species form galls; one of the larger of these infests the 
leaves of hackberry. 

The most destructive member of this family in the 

-The near- United States is the pear-tree psyllia, Psyllia pyricola. 

^Psyiiia, greatly This is a minute species, measuring only one-twelfth inch 

in length to the tip of the folded wings (Fig. 192). 
The eggs are laid early in the spring in the creases of the bark and in 
the leaf-scars of the smaller branches. The young nymphs migrate to 
the axils of the leaf petioles and the stems of the forming fruit; later 
they spread to the under side of the leaves. They secrete large quan- 
tities of honey-dew, upon which a blackish fungus grows. There are at 
least four generations each year. Badly infested trees shed their leaves 
and young fruit in midsummer. In some cases orchards have been so 
badly injured by this pest that they have been cut down by their owners. 

Family Aphidid^j 
The Plant-lice or Aphids 

The plant-lice or aphids are well-known insects; they infest nearly 
all kinds of vegetation in all parts of the country. Our most common 
examples are minute, soft-bodied, green insects, 
with long legs and antenna?, which appear on various 
plants in the house and in the field. Usually, at 
least, in each species there are both winged and 
wingless forms (Fig. 193). There are many species 
of aphids, nearly all of which are of small size ; some 
measure less than -^ of an inch in length; and our fig. i 93 . — a group of aphids. 
largest species, only \ or \ of an inch. 

The body is usually more or less pear-shaped. The winged forms 
have two pairs of delicate, transparent wings. These are furnished with 
a few simple or branched veins. The first pair of wings is larger than the 
other, and the two wings of each side are usually connected by a com- 
pound hooklet or several hamuli. The beak is three-jointed, and varies 
greatly in length; sometimes it is longer than the body. The compound 


HOMOPTERA 115 

eyes are prominent, and ocelli are also usually present. The antennas are 
from three- to seven-jointed. On the back of the sixth abdominal seg- 
ment there is, in many species, a pair of tubes, the cornicles, through 
which a wax-like material is excreted. In some genera these organs are 
merely perforated tubercles, while in still other genera they are wanting. 

Many species of aphids excrete a sweet substance known as honey- 
dew from the posterior end of the alimentary canal. It is sometimes 
produced in such quantities that it forms a glistening coating on the 
leaves of the branches below the plant-lice, and stone walks beneath 
shade-trees are often densely spotted with it. This honey-dew is fed 
upon by bees, wasps, and ants. The bees and wasps take the food 
where they find it, paying little if any attention to its source; but the 
ants recognize in the plant-lice useful auxiliaries, and often care for them 
as men care for their herds. This curious relationship will be discussed 
further in the chapter on ants. 

In addition to honey-dew, many aphids excrete a white waxy sub- 
stance. This may be in the form of powder, scattered over the surface of 
the body, or it may be in large flocculent or downy masses; every grada- 
tion between these forms exists. 

The plant-lice are remarkable for their peculiar mode of development. 
The various species differ greatly in the details of their transformation, 
but the following generalizations illustrated by the life history of the 
cabbage aphid, Brevicoryne brassicce, may be made. 

The stem-mother. — In the spring there hatches from each surviving 
egg which was laid on a cabbage stump in the fall, a female aphid known 
as the stem-mother because she gives rise to all of the succeeding genera- 
tions during the summer. She brings forth her young alive and is there- 
fore viviparous. She also bears young aphids without having mated 
(there are no male aphids in the spring) and is therefore parthenogenetic. 

The wingless agamic form. — This stem-mother gives birth to young 
which do not develop wings and which are all females. These reproduce 
parthenogenetically and are known as the wingless agamic forms. These 
reproduce their kind for a variable number of generations and then pro- 
duce the next form. 

The winged agamic form. — After a variable number of generations of 
the wingless agamic form have been developed and the food-plant has be- 
come overstocked by them, there appears a generation which is winged. 
These are all parthenogenetic, viviparous females. They are known as 
the winged agamic forms. These migrate to ether cabbage plants which 
are not overstocked with the wingless pi ant -lice. 

When the migrating winged agamic form becomes established on fresh 
plants, it produces young which are all females of the wingless agamic 
form. After a variable number of generations of the winged and wing- 
less forms have been developed and fall approaches, the egg-laying (ovip- 
arous) females and the males are produced. 

The males and oviparous females. — These are the true sexual forms. 
They pair and each female lays one or more eggs on the cabbage stump 
which rest over the winter. In the case of the cabbage aphid the ovip- 
arous female is wingless and the male is winged. Other aphids differ 
in this respect. In some species the females are winged and in a few the 
males are wingless. 

Primary and secondary host plants. — Some aphids deposit their eggs in 


7J 


116 THE STUDY OF INSECTS 

the fall on a certain plant which is called the primary host plant; but in 
the spring when the stem-mothers have appeared and have given rise to 
winged forms in the second and third generations these winged aphids 
become migrants and fly to another perhaps totally unrelated plant, 
which is called the secondary host plant. On this plant the aphids live 
during the summer but return to the primary host plants in the fall on 
which the sexes are produced and the eggs are laid. 

The potato aphid, Illinoia solanifolii, deposits its eggs in the fall on 
the rose, its primary host plant; but in the spring the winged migrants 
leave the rose and go to the potato to pass the summer. Toward fall 
winged forms appear and return to the rose where the sexual forms are 
produced and the eggs are laid. 

The rosy apple aphid, Anuraphis roseus, is another example of this 
habit. The eggs of this aphid are deposited on the apple in the fall but 
in the spring winged migrants fly to the narrow-leaved and broad-leaved 
plantains and on these plants the insects pass the summer. 

Some aphids are bark-feeding. For example, the giant hickory aphid, 
Longistigma carycz, is found feeding on the branches of hickory, maple, 
and other forest trees. It is the largest aphid known, 
measuring nearly ^ of an inch to the tips of its wings (Fig. 
194). 

Other aphids are leaf-feeding like the potato aphid al- 
fig 194. — The ready mentioned and the spring grain aphid, or "green 

Kiant hickory aphid. 1 ,, ^ „ .. „ 1 • 1 • • • • j. 1 

bug, 1 oxoptcra graminum, which is so injurious to wheat 
and oats in some seasons in the Mississippi Valley. 

There are also root-feeding species. For instance the corn-root aphid, 
Anuraphis maidiradicis, which is such a pest on the roots of corn in the 
Mississippi Valley; and the strawberry-root aphid, Aphis forbesi, which 
infests the roots of strawberry plants. Both of these species are attended 
by ants and placed upon the roots of corn and strawberries by the ants. 

Some aphids secrete great quantities of white waxy threads which 
cover their bodies like wool. These are known as the woolly aphids. 
One of these woolly aphids which occurs on the apple, is known as the 
woolly apple aphid, Eriosoma lamgera. It has a complex life history. 
Its eggs are deposited on the bark of the elm. There they hatch in the 
spring and the young crawl to the leaves and by their presence produce 
rosettes at the ends of branches. Later, winged forms go to the apple 
where several generations are produced, some of which live on the 
branches and some on the roots underground. The root form may be 
very injurious to the trees, especially in sandy soil. Finally in the autumn, 
the winged forms on the apple fly back to the elm where the sexual 
individuals are produced and the eggs are laid. It should be said that 
some of the aphids remain on the apple trees all winter. 

Large numbers of a woolly aphid are often found crowded together on 
the under side of the branches of alder. This species is known as the 
alder-blight, Prociphilus tessellata. In addition to the white excretion 
with which the body is covered this insect excretes large quantities of 
honey-dew. The result is that the branches infested by this insect, and 
those beneath the clusters of aphids, become blackened with fungi that 
grow upon this secretion. There is also a curious fungus which grows in 
large spongy masses beneath the clusters of plant-lice; this is known as 
Scorias spongiosa. It grows in the honey-dew that falls upon it. 


HOMOPTERA 


117 


The beech-tree blight, Proctphilus imbricator, infests both the twigs 
and leaves of beech. Like the preceding species it occurs in clusters of 
individuals, each of which is clothed with a conspicuous downy excretion. 
These clusters often attract attention by the curious habit that the in- 
sects have of waving their bodies up and down, the plume-like masses of 
excretion rendering them very conspicuous. When an infested limb is 
jarred the aphids emit a shower of honey-dew. Owing to the abundance 
of this secretion, the branches and leaves of an infested tree become 
blackened by growths of fungi, as with the preceding species. 

Other aphids produce galls of various shapes and sizes on the leaves 
of plants. 

The cockscomb elm-gall, Colopha ithnicola. — There are two species of 
aphids that make similar galls on the leaves of elm. These galls are 
commonly known as cockscomb elm-galls on account of their shape. 
Those made by the two species of aphids are so similar that a description 
of one will apply to the other. In each case the gall is an excrescence 
resembling a "cock's comb" in form, which rises abruptly from the upper 
surface of the leaf. It is compressed, and has its sides wrinkled perpen- 
dicularly and its summit irregularly gashed and toothed. It opens on 
the under side of the leaf by a long slit-like orifice. 

The poplar-leaf gall aphid, Thecabius populicaulis . — This aphid is 
common on several species of poplar. It makes a swelling the size of a 
small marble on the leaf at the junction of the petiole with the blade. 
This gall is of a reddish tint, and has on one side a slit-like opening. 


Fig. 195. — The witch-hazel cone-gall: a, natural size; b, section of 
gall, enlarged. (From Pergande.) 


The witch-hazel cone-gall aphid, Hormaphis hamamelidis , causes cone- 
like galls on the leaves of witch-hazel (Fig. 195). 


n8 


THE STUDY OF INSECTS 


Family Phylloxerid^ 
The Adelgids and the Phylloxerids 

In this family both the sexually perfect females and the partheno- 
genetic forms lay eggs. Moreover, the cornicles are wanting and the 
venation of the wings differs from that of the true aphids. 

Some members of this family live on conifers and cause galls on them. 
One species, Adelges abietis, lives on the Norway spruce and causes 
pineapple-shaped galls sometimes all over the tree (Fig. 196). 


Fig. 

abietis. 


196. — Gall of Adelges 


Fig. 197. — Phylloxera, root-inhabiting form: a, roots of 
Clinton vine showing the swellings; b, nymph as it appears 
when hibernating; c, d, antenna and leg of same; e,f, g, forms 
of more mature lice. (From Riley.) 


The most notorious and serious pest of this family is the grape 
phylloxera, Phylloxera vitifolice, which is a native insect on the American 
wild grape. Some of these aphids live on the foliage of the vines and 
cause small hollow galls on the leaves. Others live underground on the 
roots and cause swellings or nodules to form on the roots (Fig. 197). 
The infested roots may decay and the vines may die. In France where 
the aphid has been such a serious pest on the European type of grape it is 
the custom to use rootstocks of the native American wild grape on which 
to grow the European vines. The American rootstocks are resistant to 
the attacks of the phylloxera. 

Family Aleyrodid^e 
The Aleyrodids or White Flies 

The members of this family are small or minute insects; our more 
common species have a wing-expanse of about § of an inch. In the adult 
state both sexes have four wings, differing in this respect from the Cocci- 
dae, with which they were classed by the early entomologists. The wings 
are transparent, white, clouded or mottled with spots or bands. The 
wings, and the body as well, are covered with a whitish powder. It is 
this character that suggested the common name white flies. 


HOMOPTERA 119 

In the immature stages, these insects are scale-like in form and often 
resemble somewhat certain species of the genus Lecanium of the family 
Coccidae. Except during the first stadium, the larva? remain quiescent 
upon the leaves of the infested plant and in most species are surrounded 
or covered by a waxy excretion. In Figure 198 there 
is represented one of the many forms of this excre- 
tion. 

The members of this family feed exclusively on 
the leaves of the host-plants. With few exceptions 
they are not of economic importance ; and also with 
few exceptions, the injurious species are not widely 
distributed over the world as are many aphids 
and coccids. They are most abundant in tropical 
and semi-tropical regions. FlG - iq8 - — Ale y° des - 

The greenhouse white fly, Aster ochiton vapor ariorum, is an important 
pest of the greenhouse. It infests very many species of plants that are 
grown under glass; and sometimes it is a serious pest in the open on 
tomato and other plants that are set out after the weather is warm. 

The citrus white fly, Dialeurodes citri, is a well-known pest in the 
orange-growing sections of our country, and is also found in greenhouses 
in the North. It infests all citrus fruits grown in this country and is 
found on several other plants. 


Family Coccidae 
The Scale-insects or Bark-lice, Mealybugs, and others 

The family Coccidae includes the scale-insects or bark-lice, the mealy- 
bugs, and certain other insects for which there are no popular names. 
To this family belong many of the most serious pests of horticulturists; 
scarcely any kind of fruit is free from their attacks; and certain species 
of scale-insects and of mealybugs are constant pests in greenhouses. 
Most of the species live on the leaves and stems of plants; but some 
species infest the roots of the host-plants. The great majority of the 
species remain fixed upon their host during a part of their life-cycle, and 
can thus be transported long distances while yet alive, on fruit or on nurs- 
ery stock; this has resulted in many species becoming world-wide in dis- 
tribution. 

Happily some scale insects are useful to man. The lac-insect, Tachar- 
dia lacca, furnishes the stick-lac of commerce, from which shellac is 
made. Formerly, a red dye was obtained from the dried bodies of the 
cochineal insect, Coccus cacti, but recently this dye has been largely 
supplanted by the coal-tar dyes. China-wax is an excretion of the pe-la 
insect, Ericerus pe-la, and was formerly used in China in making candles. 

In the adult state, the two sexes of coccids differ greatly in form. The 
males are usually winged (Fig. 199, ib); in a few species they are either 
wingless or have vestigial wings. The fore wings are usually large, com- 
pared with the size of the body; the hind wings are always greatly 
reduced in size; usually they are a pair of club-shaped halteres, but in a 
few forms they are more or less wing-like. Each hind wing is furnished 
with a bristle, which is hooked at the end and fits into a pocket or fold 


120 


THE STUDY OF INSECTS 


Fig. igg. — Chionaspis furfura: i , scales on pear, natural size; ia, scale of male, ib, adult 
male, ic, scale of female, enlarged. 

on the inner margin of the fore wing of the same side; in a few species 
there are two or three or more of these hamuli. 

The legs are wanting in many adult females, having been lost during 
the metamorphosis. In adult males they are of ordinary form; except 
in a few species, the tarsi are one-jointed, and each is furnished with a 
single claw. 

The caudal end of the abdomen of the male usually bears a slender 
tubular process, the stylus. 

The female coccid is always wingless, and the body is either scale- 
like or gall-like in form, or grub-like and clothed with wax. The waxy 
covering may be in the form of powder, of large tufts or plates, of a con- 
tinuous layer, or of a thin scale, beneath which the insect lives. The 
antennas in many species are entirely wanting in the adult females. 

The mouth-parts of the adult males are lacking and they do not take 
food. In the case of the females of the more common species the maxil- 
lary and mandibular seta? are long and well developed for penetrating 
the tissues of plants. 

THE MOTILE COCCIDS 

We usually think of scale insects as fixed on a host-plant and unable 
to move about. There are, however, several subfamilies of coccids, the 
members of which are so generalized that the nymphs and adults possess 


HOMOPTERA 


normal, functional legs and are capable of movement over the host-plant 
although the amount of movement by these forms is usually not great. 
Jn fact some of the tortoise scales are practically fixed. 

The division into motile and non-motile forms is a purely artificial 
one used for the sake of a clearer understanding of these important insects. 

The cottony-cushion scale, Iccrya purchasi. — This beautiful insect 
(Fig. 200) was at one time the most dangerous insect pest in California, 
and did a great amount of injury. It is an introduced Australian species, 
and has been subdued to a great extent by the introduction of an Aus- 
tralian lady-bug, Rodolia cardinalis , which preys upon it. The body of 
the adult female is scale-like, dark orange-red, and has the dorsal surface 
more or less covered with a white or yellowish-white powder. The insect 
secretes a large egg-sac, which is beautifully ribbed. 


Fig. 200. — Icerya purchasi. 
and young, on orange. 


Females, adult 


Fig. 201. — Orthezia, enlarged. 


Orthezia. — The 


■ Pseadococcus longi- 
enlarged. 


threads like wool. 


members of this genus occur not uncommonly on 
various weeds. They are remarkable for the 
calcareous secretion with which the body is 
clothed. This is in the form of long plates. Fig- 
ure 201 represents a nymph; in the adult female 
the secretion becomes more elongated posteriorly, 
and forms a sac containing the eggs mixed with 
a fine down. Later, when the young are born, 
they remain in the sac till they have themselves 
secreted a sufficient amount of the lamellar mat- 
ter to cover them. 

The mealybugs. — The mealybugs are com- 
mon pests in greenhouses all over this country, 
especially the long-tailed mealybug, Pseudococcus 
longispinus (Fig. 202). In California there are 
several species which live in the open and become 
serious pests to citrus trees. Mealybugs excrete 
a white waxy material which may be in the form 
of a white powder over the body or of white 


122 


THE STUDY OF INSECTS 


The tortoise or soft scales. — The tortoise scales are so-called because 
the bodies of the females are usually shaped like the shell of a tortoise. 
The body of the female is cleft at the caudal end and, in our more 
common forms, is unprotected by wax or other form of covering. They 
are, therefore, often called soft scales. 

Legs are present in the first and usually in the second stage nymphs 
and the first stage nymphs are especially active. The adult females 
are usually well fixed to their host-plant. 

Many of them excrete very little wax, the body being practically 
naked, and the eggs, or the young in the viviparous species, are deposited 
beneath the body; in other species, although the body is nearly naked, 
the adult female excretes a large, cottony egg-sac; and in still others the 
body is deeply encased in wax. 

The soft scale, Lecanium hesperidum, is the commonest and most 
widely spread member of this subfamily; it infests a great variety of 
plants; in the North, it is very common in greenhouses; in the warmer 
parts of the country it lives out of doors. See Figure 206b, page 124. 

The members of the genus, 
Puhinaria, include species in 
which the body of the fe- 
male resembles Lecanium but 
which excrete a large cottony 
egg-sac. The cottony maple 
scale, Puhinaria vitis, is 
common on the maple, osage 
orange, grape, and other 


Fig. 203. — Puhinaria vitis. 
sacs, on grape, natural size 

plants (Fig. 203). 


Females, with large cottony egg- 


THE NON-MOTILE COCCIDS 

The greater number of the common 
scale insects of this country, especially 
those which are of economic importance, 
are fixed to the host-plant in the adult 
(female) stage. The legs of the newly 
hatched female nymphs are lost in the first 
molt and the adult female becomes incap- 
able of movement. 

The armored scales. — The great ma- 
jority of the common scale insects of this 
country differ from the forms already de- 
scribed in that the body of the insect, 
except for a very short period after birth, 
is covered with a scale composed in part 
of a waxy excretion of the insect and 
partly of molted skins. In the lecaniums 
the scale-like object is the body of the 
insect ; but in the case of the oyster-shell 
bark-louse (Fig. 204), the San Jose scale 
and of many other forms, the scale-like object commonly seen is not the 
insect, but a waxy armor beneath which it lives. 

The young insects of this group resemble in general appearance those 


Fig. 204. — The oyster-shell bark louse, 
Lepidosaphes ulmi; the young appear as white 
dots. 


HOMOPTERA 


123 


of other scale insects. Their active stage, however, is much shorter. 
After crawling about over the twigs of a tree for a few days, the young 
scale insect settles upon a suitable place and immediately begins to 
excrete fine threads of wax which soon become compacted into a thin 
pellicle covering the body. As the insect grows and sheds its skin, this 
cast skin is joined to the excretion and forms a part of the scale. This is 
the bright-colored, nipple-like prominence, seen in the center of the San 
Jose's scale and of the red scale of the orange; and two of them may be 
seen at the smaller end of the scale of the oyster-shell bark-louse. The 
position of the cast skins in the scale differs in different genera, and forms 
a good character for classification. 


JbamM. 


Fig. 205. — Chionaspis pinifoliir: 2, scales on Pinus strobus, natural size, leaves stunted; 2a, leaves 
not stunted by coccids; 2b, scale of female, usual form, enlarged; 2c, scale of female, wide form, en- 
larged; 2d, scale of male, enlarged. 

Closely allied species differ but little in the form of the scale. To 
distinguish these it is necessary to study the insects themselves, which are 
found beneath the scales. The distinctions between closely allied species 
are such that it requires very close observation and much skill in this 
particular line to make the determinations, a careful preparation of the 
specimens and an excellent microscope being necessary requisites. 

The different species of scale-insects vary as regards their food 
habits. We find that certain species infest particular plants and will feed 
upon no others; thus, the red-scale of the orange does not trouble decid- 
uous fruits. On the other hand, other species have a wide range of 
food plants. This is true of the San Jose scale, which infests a great 
variety of both cultivated and wild plants. 

Figure 205, represents the well-known pine-leaf scale, Chionaspis 


124 


THE STUDY OF INSECTS 


pinifolice, which occurs on various species of pine wherever these trees 
grow in the United States; Figure 199 represents the scurfy scale Chionaspis 
furfura, which is very destructive to apples and pears; while the San Jose 
scale, Aspidiotus pernicidsus, which is one of the most serious pests of vari- 
ous fruit trees in this country, is shown in Figure 206. 


Fig. 206. — San Jose scale, 
much enlarged. 


Fig. 206a, — Pseudococcus cilri, 
a mealybug that is a pest in green- 
houses and of orange trees in warm Fig. 200b, 
regions. natural size. 


Lecanium hcspcridum, adult females, 


CHAPTER XIX 
ORDER DERMAPTERA* 


The Earwigs 

The winged members of this order usually have four wings; but in some 
of them the hind icings are -vestigial or wanting; the fore wings are leathery, 
very small, without veins, and when at rest meet in a straight line on the 
back; the hind wings, when well developed, are large, with radiating veins, 
and when at rest are folded both lengthwise and crosswise. The mouth- 
parts are formed for chewing. The caudal end of the body is furnished with 
a pair of appendages, the cerci, which resemble forceps. The metamorphosis 
is incomplete. 

These are long, narrow-bodied insects with short, 
thickened fore wings which, when at rest, meet in a 
straight line on the back (Fig. 207). They Can be 
distinguished from beetles by the pair of forceps-like 
appendages, the cerci, at the caudal end of the body. 
The common name, earwig, was given these in- 
sects in England, and has reference to a widely 
spread fancy that these insects creep into the ears 
of sleeping persons. The earwigs are more common 
in this country in the South and on the Pacific Coast. 
They are nocturnal in habits and feed on flowers, 
fruits and vegetables and some species feed on ani- 
mal matter, especially dead 
insects. 

The fore wings resemble 
the elytra of beetles but the 
hind wings are very different 
from those of any other in- 
sects. Figure 208 represents one of these; 
are furnished with radiating veins which extend 
from a point some distance from the base of the wings. When the wing is 
not in use that part over which these veins extend is folded in plaits like a 
fan, after which the wing is folded twice crosswise. 

The most distinctive feature of the earwigs is the form of the cerci 
which are forceps-like and usually prominent. They are usually larger 
in the male than in the female. 

There are only about fifteen known species of earwigs in America 
north of Mexico and some of these are exotic forms which have come 
into the country through the channels of commerce. 

The little earwig, Labia minor, is only about \ of an inch long but it 
is widely distributed in the United States and has become established in 
Canada (Fig. 207). 

* Dermaptera: derma (Stpua), skin; pteron (irrepov), a wing. 
125 


Fig. 207. — An 
wig, Labia minor. 


Fig. 208. — Wing of earwig. 


they 


126 


THE STUDY OF INSECTS 


The seaside earwig, Anisolabis marliima, which is about f of an 
inch in length, is found along the Atlantic Coast from Maine to Texas. 
Both pairs of wings are absent in this species. 

The handsome earwig, Prolabia pulchella, is a shining chestnut-brown 


Fig. 209. — A , Male with short forceps; 
B, forceps of female; C, long type of forceps 
of male. (After Morse.) 

species found in the southern United States under the bark of dead trees. 
It is about \ of an inch in length. 

The European earwig, Forjicula auriculdria, (Fig. 209), was found at 
Newport, Rhode Island, in 191 1 and has now become established in the 
vStates of New York, Oregon, Washington and California. It is about f of 
an inch in length and of a rich reddish-brown with the wing-covers and legs 
a dull yellowish-brown. This earwig is nearly omnivorous although it is 
especially injurious to flowers and green plants. It often occurs in great 
numbers and becomes a serious pest. 


CHAPTER XX 
ORDER COLEOPTERA* 

The Beetles 

The winged members of this order have four wings; but the wings of the 
first pair are greatly thickened, forming "wing-covers" or elytra, beneath 
which the membranous hind wings are folded when at rest. The elytra meet 
in a straight line along the middle of the back and serve as armor, protecting 
that part of the body which they cover. The mouth-parts are formed for 
chewing. The metamorphosis is complete. 

The order Coleoptera includes only the beetles. 
These insects can be readily distinguished from all 
others except the earwigs by the structure of the 
fore wings, these being horny, veinless " wing- 
covers " or elytra, which meet in a straight line 
along the middle of the back (Fig. 210); and they 
differ from earwigs in lacking pincer-like ap- 
pendages at the caudal end of the body. Beetles 
also differ from earwigs in having a complete 
metamorphosis. FlG - 2I °- 

The hind wings are membranous, and in most species very efficient 
organs of flight. But in some of the pre-eminently running beetles the 
hind wings are wanting, and the elytra serve only as a protection to the 
abdomen. With some of these insects the elytra are even grown together 
where they meet on the middle line of the back; and in some of the 
Meloidae the elytra do not meet in a straight line. 

The venation of the wings of the Coleoptera has become greatly 
modified, and, consequently, the determination of the homologies of the 
wing veins is a difficult matter. The transformation of the fore wings 
into elytra has resulted in a great reduction of their venation; and the 
foldings of the hind wings interrupt the veins and cause distortions in 
their courses. 

The different mouth-parts are very evenly developed; we do not find 
some of them greatly enlarged at the expense of others, as in several 
other orders of insects. The upper lip, or labrum, is usually distinct; the 
mandibles are powerful jaws fitted either for seizing prey or for gnawing; 
the maxillae are also well developed and are quite complicated, consisting 
of several distinct pieces; the maxillary palpi are usually prominent; 
and the lower lip, or labium, is also well developed and complicated, con- 
sisting of several parts and bearing prominent labial palpi. 

The larvas are commonly called grubs. They are usually furnished 
with six thoracic legs, and often with a single proleg at the caudal end of 
the body; some, however, as the larvae of the snout-beetles, are entirely 
* Coleoptera: coleos (/coXeos), a sheath; pteron (wrepov), a wing. 

127 


128 


THE STUDY OF INSECTS 


Fig. 211. 


destitute of jointed legs. The pupae have the partially developed elytra, 
wings, and legs folded upon the breast, but in distinct sheaths (Fig. 211). 
These insects usually transform in rude cocoons made of earth or 
of bits of wood fastened together by a viscid substance excreted 
by the larvae. Many wood-burrowing species transform in the 
tunnels made by the larvae; and some of the dermestids as well 
as some of the lady-bugs transform in the last larval skin. 

Both larvae and adults present a very wide range of habits. 
While the majority of the species are terrestrial, the members of 
several families are aquatic; and while some feed on vegetable 
matter, others feed upon animal matter. The vegetable feeders 
include those that eat the living parts of plants, those that bore in dead 
wood, and those that feed upon decaying vegetable substances. Among 
the animal feeders are those that are predacious, those that feed on dried 
parts of animals, and those that act as scavengers, feeding on decaying 
animal matter. Viewed from the human standpoint, some species are 
very beneficial, others are extremely noxious. 

In the classification of beetles much use is being made of the varia- 
tions in form of the ventral and lateral sclerites of the thorax. Figure 
215 will serve as an illustration of these sclerites. One feature merits 
special mention: the coxae of the hind legs are flattened and immovably 
attached to the thorax so that they appear to be a part of the thorax 
instead of the basal segment of an appendage. 

The Coleoptera is a very large order, the latest catalogue listing 
18,547 species representing 109 families. The order is divided into two 
suborders, the Adephaga and the Polyphaga. 

CLASSIFICATION OF THE COLEOPTERA 

In order to use the table for determining the families of beetles it is 
necessary that the student should become familiar with certain terms not 
defined in the discussion of the external anatomy of insects. The follow- 
ing notes are therefore given as a supplement to that discussion. 

The head. — One of the sclerites that enters into the 
composition of the external wall of the head is frequently 
referred to in descriptions of beetles; this is the gula. 
The gula is the central portion of the ventral wall of the 
head, and is the part which bears the labium (Fig. 212, g). 

The sutures which bound the 
gula, one on each side, are 
termed the gular sutures (Fig. 
2 1 2 , gs) . In the Rhynchop- 
hora the gula appears to be 
wanting, and there is a single 
suture on the middle line of 
the head (Fig. 213, gs.) 

The antenna. — The 
more common types of an- 
tennae have been described. 
In many insects however, (£ r ^ t J s e ' s c 
the first segment of the an- 
tenna is long and the an- 
tenna is bent suddenly at the joint between the first and second seg 
ments; such antennae are said to be elbowed or geniculate. 


Fig. 212. — Head of Ilarpalus, ventral 
aspect: a, antenna; g, g, gula; ga, galea 
or outer lobe of the maxilla; gs, gular 
suture; //>, labial palpus; m, m, mandibles; 
mp, maxillary palpus; s, submentum. 


Fig. 213. — Head and 
prothorax of Rhyn, lio- 


proster- 
em, epimerum; 

/, femur. 


COLEOPTERA 


129 


The mouth-parts. — Much use is made of the form of the parts of the 
labium or lower lip in descriptions of beetles. When fully developed the 
labium consists of three principal parts and a pair of appendages. The 
principal parts are the submentum, the mentum, and the Ugula; the ap- 
pendages are the labial palpi. The basal part of the labium, the part 
which is joined to the gula, is the submentum (Fig. 214, sm). By an un- 
fortunate error this sclerite is almost invariably described in works on 
the Coleoptera as the 'mentum. This fact should be borne in mind by 
the student when using any of the older books on this subject. The 
intermediate portion of the labium is the mentum (Fig. 214, m); and the 
distal portion the Ugula. 

The ventral aspect of a beetle. — In the classification of beetles much 


Fig. 214. — Labium of Harpalus: sm, sub- 
mentum; in, mentum; lig, ligula; P, labial 
palpus. 


Fig. 215. — Ventral aspect of a beetle, Enchroma gigantea: 
Fig. 214a. — Maxilla of beetle; a, cardo; A, prothorax; B, mesothorax; C, metathorax; c, c, c, coxae; 
■ stl .P f r s ; c . palpifer; d, palpus; /, galea; em, em, em, epimera; es, es, es, episterna; s, s, s, sterna; /, I, 
g, lacinia; /;, digitus. trochantins; x, elytrum; y, antecoxal piece of metasternum. 

use is made of certain sclerites and sutures present on the ventral side 
of the insect. The student should study Figure 215 to become familiar 
with these structures. In some beetles the metasternum is divided 
into two unequal portions by a suture which extends transversely a short 
distance in front of the caudal margin ; the smaller sclerite which borders 
the posterior coxas in front and often passes between them is called 
the ante-coxal piece of the metasterum (Fig. 215, y). 


13° 


THE STUDY OF INSECTS 


The openings in the thoracic segments in which the legs are inserted 
are termed the coxal cavities. Much use is made in the classification of 


Fig. 216. — Prothorax of IJarpalus, ven- 
tral aspect: c, coxa; em, epimerum; es, 
episternum; /, femur; n, pronotum; s, s, 
s, prosternum. 


Fig. 217. — Prothorax of Pentlie; c, 
coxa; cc, coxal cavity; /, femur; s, pros- 
ternum; tr, trochanter. 


beetles of the form of the coxal cavities of the prothorax. When the 
epimera of the prothorax extend behind the coxae and reach the pros- 
ternum, the coxal cavities are said to be closed (Fig. 216); when the 
epimera do not extend behind the coxae to the prosternum, the coxal 
cavities are described as open (Fig. 217). 

The tarsi of certain beetles. — In the suborder, Polyphaga, there is a 
group of beetles, the Phytophaga, in which the tarsi appear to be four- 
segmented. The fourth segment is a very small one situated deep in be- 
tween the lobes of the third segment and is firmly united with the fifth 
segment (Fig. 218, A). Other types of tarsi in the series Palpicornia, Poly- 
formia, and Clavicornia are shown in Figure 218. 


Fig. 218. — Tarsi of beetles: A. PhytophaRa; B, C, 
D, of the series Palpicornia, Polyformia, and Clavicornia. 


TABLES FOR DETERMINING THE FAMILIES OF THE 

COLEOPTERA DISCUSSED IN THIS MANUAL 

TABLE I. — THE SUBORDERS 

A. Ventral part of the first segment of the abdomen divided by the hind coxal 
cavities, so that the sides are separated from the very small medial part. Suture 


COLEOPTERA 131 

present between pronotum and episternum. Suborder Adephaga; see Table II. 
AA. Ventral part of the first segment of the abdomen visible for its entire breadth. 
Suture between pronotum and episternum not present. Suborder Polyphaga; 
See Table III. 

TABLE II. — ADEPHAGA, THE FAMILIES OF THE SUBORDER 

A. Metasternum with an aritecoxal piece, separated by a well-marked suture reaching 

from one side to the other and extending in a triangular process between the 

hind coxae. Hind coxa? mobile, and of the usual form; habits terrestrial; 

legs fitted for walking. 

B. Antennas inserted on the front above the base of the mandibles. p. 135. 

ClCINDELIDyE 

BB. Antennas arising at the side of the head between the base of the mandibles 
and the eyes. Beetles with long flat bodies and with the scutellum visible. 

p. 136 CARABID/E 

AA. Metasternum without an antecoxal piece; legs fitted for swimming. 

B. With only two eyes; antennas filiform, p. 138 DytisciDjE 

BB. With four eyes, two above and two below; antennas short and modified in 
form. p. 139 Gyrinid^e 

TABLE III. — POLYPHAGA, THE SERIES OF FAMILIES OF THE 

SUBORDER 

A. Head not prolonged into a narrow beak, palpi always flexible; two gula sutures 
at least before and behind (Fig. 212); sutures between the presternum and the 
episterna and epimera distinct (Fig. 216); the epimera of the prothorax not 
meeting on the middle line behind the presternum (Fig. 216). 
B. Abdomen with at least three corneous segments dorsally, and exposed more or 
less by the short elytra. Hind wings with simple, straight veins; antennas 
variable, but never lamellate. Series Brachelytra; see Table IV. 
BB. Abdomen with at most two corneous segments dorsally, usually completely 
covered by the elytra; hind wings with veins in part connected by recurrent 
veins. 
C. Antennas clubbed or not, but if clubbed not lamellate. 

D. Tarsi usually apparently four-jointed, the real fourth segment being 
reduced in size so as to form an indistinct segment at the base of the 
last segment, with which it is immovably united (Fig. 218, A); the first 
three segments of the tarsi dilated and brush-like beneath; the third 
segment bilobed. Series Phytophaga; see Table VII. 
DD. Tarsi varying in form and in the number of the segments, but when 
five-jointed not of the type described under D above, the joint between 
the fourth and fifth segments being flexible. Series Palpicornia, Poly- 
formia, and Clavicornia; see Table V. 
CC. Antennas with a lamellate club. Series Lamellicornia; see Table VI. 
AA. Head either prolonged into a beak or not; palpi usually short and rigid; 
gular sutures confluent on the median line (Fig. 213, gs); prosternal sutures 
wanting; the epimera of the prothorax meeting on the middle line behind the 
presternum (Fig. 213, em). Series Rhynchophora; see Table VIII. 

TABLE IV. — THE FAMILIES OF THE BRACHELYTRA 

A. Elytra short, leaving the greater part of the abdomen exposed; the suture between 
the elytra when closed straight; wings present, and when not in use folded 
beneath the short elytra; the dorsal part of the abdominal segments entirely 
horny; abdomen flexible, and with seven or eight segments visible below; an- 
tennas not clubbed at the ends, p 143 Staphylinid/e 

AA. Elytra usually longer, covering the greater part of the abdomen ; when short the 
wings are wanting or, if present, may or may not be folded under the short 
elytra when at rest; the dorsal part of the abdominal segments partly mem- 
branous; antennas usually clubbed at the ends. 
B. Hind tarsi five-segmented, antennas rarely elbowed, abdomen with six or more 
ventral segments, anterior coxas conical. 


i32 THE STUDY OF INSECTS 

C. Posterior coxa' widely separated, eyes wanting or inconspicuous, p. 142. 

SlLPHIDJE 

CC\ Posterior coxae approximate, and not laminate, eyes with small facets. 

p. 142., SlI.PHID/E 

BB. All tarsi four-segmented ; hind coxae contiguous and with plates covering 
the femora entirely or in part. p. 142 Silphid^e 

BBB. Hind tarsi with only four segments; the fore tarsi, and almost always the 
middle tarsi with five segments, p. 142 SilphiDjE 

TABLE V. — THE FAMILIES OF THE PALPICORNIA, POLYFORMIA, 

AND CLAVICORNIA* 

It is impracticable to separate these three series of families in these tables, owing 
to the fact that characters sharply separating them have not been found. 
A. Hind tarsi five-jointed. 

B. Maxillary palpi as long as or longer than the antennas, p. 141 .. . .HvDROPHiUDyE 
BB. Maxillary palpi much shorter than the antennae. 

C. Tarsal claws very large; the first three abdominal segments grown together 

on the ventral side Psephenidce, Dryopida, Elmida 

CC. Tarsal claws of usual size; ventral abdominal segments usually free, some- 
times (Buprestidae) the first two grown together. 
D. Abdomen with not more than five ventral segments. 

E. Femur joined to the apex or very near the apex of the trochanter. 

Ptinida, Anobiidce, Bostrichida, Lyctida 

EE. Femur joined to the side of the trochanter. 

F. Anterior coxae globular or transverse, usually projecting but little from 
the coxal cavity. 
G. Anterior coxa transverse, more or less cylindrical, posterior coxae 
grooved for the reception of the femora. 

Nosodendridcc, Byrrhidce, Chelonariidce, et al. 

GG. Anterior coxae globular. 

H. Presternum with a process which extends backward into a groove 
in the mesosternum. 

I. Eye continuing the general line of the head, the head usually 

buried in the thorax up to the eye. Prothorax closely dove- 
tailed into mesothorax below. First ventral suture of abdomen 
much weaker than the others, usually partly lost. p. 148. 

BUPRESTID/E 

II. Eye usually prominent, frequently separated by a space from 
prothorax; articulation between pro- and mesothorax usually 
freely movable; first three ventral sutures of abdomen similar 
and deep. ( Not movable as usually reporte.) p. 147 . . . Elaterid/e 

HH. Presternum without a process received by the mesosternum, 
although it may be prolonged so as to meet the mesosternum. 

I. Posterior coxae contiguous Phalacridce 

II. Posterior coxae separated. 

J. Body depressed; middle coxal cavities not closed externally 
by a meeting of the mesosternum and metasternum. p. 152. 

CuCUJIDjE 

JJ. Body more or less convex; middle coxal cavities entirely 
surrounded by the sterna. 

Mycetophagidce, Cryptophagidcc, ErotylidcB 

FF. Anterior coxae conical, and projecting prominently from the coxal 
cavity. 
G. Posterior coxae dilated into plates partly protecting the femora, at 
least at their bases. 

H. Antennae serrate or flabellate Rhipiceridce 

HH. Antennae with the last three segments forming a large club. 

I. Tarsi with second and third segments lobed beneath. . . .Byturida 

II. Tarsi simple, p. 150 Dermestid^e 

DD. Abdomen with six or more ventral segments. 

E. Anterior coxae globular Cebrionidce, Plastoceridce 

EE. Anterior coxae conical. 

* Families italicized are not discussed in this manual. 


COLEOPTERA 


i33 


F. Posterior coxas not prominent, flat, covered by the femora in repose. 

Cleridce, Corynetida 

FF. Posterior coxas more or less conical and prominent at least internally, 
not covered by the femora in repose. 
G. Anterior coxae long, with distinct trochantins. 
H. Abdomen with seven or eight ventral segments. 
I. Middle coxae contiguous; epipleurae distinct. 

J. Episterna of metathorax sinuate on inner side, epipleurae 
usually wide at the base. 
K. Head more or less covered; antennae approximate or 
moderately distant; metathoracic epimera long. p. 144. 

Lamfyrid^e 

KK. Head exposed; antennae distant; metathoracic epimera 

wide PhejigodidcB 

JJ. Episterna of metathorax not sinuate on the inner side; 

epipleurae narrow at the base. p. 145 Cantharid^e 

AA. Hind tarsi either only three-jointed, or four-jointed but apparently only three- 
jointed, the third joint being small and concealed in a notch at the end of the 
second joint. (See also AAA.) 
B. Wings fringed with long hairs. A minute aquatic species from S. Cal. and 

Ariz. {Hydroscapha.) p. 141 Hydrophiud^e 

BB. Wings not fringed with hairs. 

C. Tarsi with second segment dilated. 

D. Tarsal claws appendiculate or toothed; first ventral abdominal segment 

with distinct curved coxal lines, p. 152 Coccinellid^e 

DD. Tarsal claws simple; first ventral abdominal segment without coxal 

lines Endomychidce 

AAA. Hind tarsi with only four segments; the fore tarsi, and almost always the 
middle tarsi also, with five segments. 
B. Anterior coxal cavities closed behind. 
C. Tarsal claws simple. 

D. Abdomen with five ventral segments. 

E. Ventral abdominal segments in part grown together. 

F. Next to the last segment of the tarsi spongy beneath Lagriidce 

FF. Penultimate segment of tarsi not spongy, p. 151 Tenebrionid^e 

BB. Anterior coxal cavities open behind. 

C. Head not strongly and suddenly constricted at base. 
D. Middle coxas not very prominent, antennas free. 
E. Prothorax margined at the sides. 

F. Middle coxal cavities entirely surrounded by the sterna. 

Cryptophagidce 

FF. Epimera of mesothorax reaching the coxae. 

G. Metasternum long; epimera of metathorax visible. .Melandryida 
GG. Metasternum quadrate; epimera of metathorax covered, p. 152. 

Cucujid^e 

EE. Prothorax not margined at the sides Pythidce 

DD. Middle coxas very prominent (Edemeridtz 

CC. Head strongly constricted at base. 

D. Head prolonged behind and gradually narrowed Cephaloidcc 

DD. Head suddenly narrowed behind. 

E. Hind coxas not prominent or but slightly so, anterior coxas globular, not 

prominent, p. 152 Cucujid^e 

EE. Hind coxas large, prominent. 

F. Tarsal claws simple; head horizontal Pyrochroidce 

FF. Claws cleft or toothed, front vertical, p. 145 .Meloide: 


TABLE VI. — THE FAMILIES OF THE LAMELLICORNIA 

A. Plates composing the club of the antennas flattened and capable of close apposi- 
tion. 

B. Abdomen with six visible ventral segments, p. 154 Scarab,eid.e 

BB, Abdomen with five visible ventral segments. 


134 


THE STUDY OF INSECTS 


C. Epimera of mesothorax attaining the oblique coxae, p. 154 . . . . Scarab/Eid^e 

CC. Epimera of mesothorax not attaining the coxae, p. 159 Trogid^e 

AA. Plates composing the club of the antennae not capable of close apposition, and 
usually not flattened. 
B. Men turn deeply emarginate, ligula filling the emargination. p. 160. .Passalid.^ 
BB. Mentum entire, ligula covered by the mentum or at its apex. p. 159. 

LuCANIDvE 

TABLE VII. — FAMILIES OF THE PHYTOPHAGA 

This series includes three families, which are so connected by intermediate forms 
that it is not easy to separate them. The . following table will aid the student in 
separating the more typical forms. 
A. Body elongate; antennae almost always long, often as long as the body or longer. 

The larvae are borers, p. 160 CerambyciDjE 

AA. Body short and more or less oval; antennae short. 

B. Front prolonged into a broad quadrate beak; elytra rather short so that the 
tip of the abdomen is always exposed. The larvae live in seeds, p. 167. 

Mylabrid^e 

BB. Front not prolonged into a beak; usually the tip of the abdomen is covered 
by the elytra. Both larvae and adults feed on the leaves of plants, p. 164. 
ChRYSOMELIDjE 

TABLE VIII. — THE FAMILIES OF THE RHYNCHOPHORA 
(Compiled from Blatchley and Leng) 
A. Beak rarely absent, usually longer than broad; tibiae never with a series of teeth 
externally. 
B. Antennae straight without a distinct club, though with the outer joints often 
more or less thickened; beak present at least in the female and pointing 
directly forward; form usually very slender and elongate, p. 169. . . Brentid/E 
BB. Antennae straight or elbowed, always with a distinct club. 

C. Palpi flexible; antennal club rarely compact; beak always short and broad; 
labrum present; thorax with a transverse raised line which is either ante- 
basal or basal, p. 169 Platystomid/e 

CC. Palpi rigid and labrum wanting except in the subfamily, Rhinomacerinae 
antennal club usually compact; beak variable in length, often long and 

curved downwards, p. 169 Curculionid^e 

AA. Beak absent or extremely short and broad; tibiae with a series of teeth ex- 
ternally, or, if these are wanting, with a prominent curved spine at apex; an- 
tennae short, but little longer than the head, always elbowed, and with a compact 
club except in Phthorophoelus where the club is lamellate; palpi rigid; body 
short, subcylindrical or rarely oval. 
B. Anterior tarsi with the first segment longer than the second, third and fourth 

together, p. 171 Platypodia: 

BB. Anterior tarsi with the first segment shorter than the second, third, and fourth 
together, p. 172 Scolytid^e 

THE CARNIVOROUS BEETLES 

Suborder Adephaga * 

The name of this suborder, Adephaga, was 
suggested by the predacious habits of its 
members. These beetles are distinguished 
from other Coleoptera by the presence of a 
suture on each side of the prothorax separat- 
ing the pleurum from the notum, and by the 
fact that the ventral part of the first segment 
of- the abdomen is divided by the hind 
coxal cavities so that the sides are separated 
from the very small medial part (Fig. 219). 

The larvae are campodeiform, and differ from all other beetle larvae in 
* Adephaga: adephagous (kb-qdyayos) , voracious. 


1 st A 


Fig. 2iq. — Ventral aspect of part of 
thorax and abdomen of Galerita janus: 1st 
A, first abdominal segment; 2d, A, second 
abdominal segment. 


COLEOPTERA 


i35 


that their legs are six-jointed except in a single exotic species; this is 
one more segment than is found in the legs of other beetle larvae. The 
legs are usually furnished with two claws, whereas the legs of other coleop- 
terous larvas are one-clawed. 

This suborder is represented in North America by less than ten fam- 
ilies. 

Family Cicindelid^; 

The Tiger-beetles 

The graceful forms and beautiful colors of the greater number of the 
tiger-beetles, those of the genus Cicindela, have made the family one of 
the favorites of students of Coleoptera. Their popular name is suggestive 
of their predacious habits, and of the stripes with which many are 
marked. They are usually a metallic green or bronze, banded or spotted 
with yellow. Some are black; and some that live on white sand are 
grayish-white, being exactly like 
the sand in color. Figure 220 
represents a common species of 
Cicindela. 

A useful character for distin- 
guishing the members of this 
family is the fact that the terminal 
hook of the maxilla (the digitus) 
is united to this organ by a mov- 
able joint (Fig. 221, h). FlG ' 22a FlG - 22T - FlG ' 222 " 

The tiger-beetle larvas (Fig. 222) are as ugly and ungraceful as the 
adults are beautiful. The two have only one habit in common — their 
eagerness for prey. The larvae live in vertical burrows in sandy places or 
in beaten paths. These burrows occur also in ploughed fields that have 
become dry and hard. They often extend a foot or more in depth. The 
larva takes a position of watchfulness at the mouth of its burrow. Its 
dirt-colored head is bent at right angles to its lighter-colored body and 
makes a neat plug to the opening of the hole. Its rapacious jaws extend 
upward, wide open, ready to seize the first unwary insect that walks 
over this living trap, or near it; for a larva will throw its body forward 
some distance in order to seize its prey. On the fifth segment of the 
abdomen there is a hump, and on this hump are two hooks curved for- 
ward. This is an arrangement by which the little rascal can hold back 
and keep from being jerked out of its hole when it gets some large insect 
by the leg, and by which it can drag its struggling prey down into its 
lair, where it may eat it at leisure. It is interesting to thrust a straw 
down into one of these burrows, and then dig it out with a trowel. The 
chances are that you will find the indignant inhabitant at the remote end 
of the burrow, chewing savagely at the end of the intruding straw. 

One hundred and fourteen species of tiger-beetles are now listed in 
our fauna; these represent four genera, the principal one of which is the 
genus Cicindela containing at least 76 species and many varieties. 

The members of this genus, unlike most other members of the family, 
are diurnal in habit. They are found on bright, hot days in dusty roads, 
in beaten paths, and on the shores of streams. They are the most agile 
of all beetles; and they are not merely swift of foot, but are also able to 


i 3 6 THE STUDY OF INSECTS 

fly well. When approached, they remain still until we can see them well 
but are still out of reach; then like a flash they fly up and away, alight- 
ing several rods ahead of us. Before alighting they usually turn so 
that they face us, and can thus watch our movements. They hide by 
night and in cloudy or rainy weather in holes in the ground or beneath 
stones or rubbish. The beetles have been found hibernating, each in a 
separate burrow extending under a stone. We have seen 
them in September digging burrows in a hillside; these 
descended slightly and were about five inches deep. The 
beetles kicked the dirt out behind them as they dug, so 
that it lay in a heap at the opening of the hole. 

There are two species of the genus Tetracha (Fig. 223) 
widely distributed in the United States. The species, Am- 
blycheila cylindriformis , found from Kansas to New Mexico 
is a very large one for it is nearly 1? inches long. Over 
Fig. 22.?. — Tetra- thirty species of the genus ( huus are found along the Pacific 
coast. These beetles are nocturnal : they search for their 
prey at night. 

Family CarabievE 
The Ground-beetles 

The ground-beetles are so called because they are very common on 
the surface of the ground, lurking under stones or rubbish, where they hide 
by day. At night they roam about in search of their prey. Our more 
common species are easily recognized by their shining black color and 
long legs. On the Pacific Coast, however, the darkling beetles (Family 
Tenebrionidae) , which are also black and have long legs, abound under 
stones and fragments of wood on the ground. But the two families can 
be easily distinguished by the fact that in the ground-beetles all the tarsi 
are five-jointed, while in the darkling beetles the hind tarsi are only 
four-jointed; and the darkling beetles do not run rapidly as do the 
ground-beetles. 

With the ground-beetles, the antennae are thread-like, tapering gradu- 
ally towards the tip, and each segment is of nearly uniform thickness 
throughout its length; the legs are fitted for running, and the antennas 
are inserted between the base of the mandibles and the eyes. Although 
most of the species are black, there are those that are blue, green, or 
brown, and a few that are spotted. The wing-covers are almost always 
ornamented with longitudinal ridges and rows of punctures. 

Most members of this family are predacious, feeding upon 
other insects, which they spring upon or capture by chase. A few 
species use vegetable food ; but their depredations are rarely of eco- 
nomic importance. As there are more than two thousand described 
North American species, and as many of the species are very com- 
mon, this family may be considered the most important family of 
the predacious insects. 

The larvae of ground-beetles are generally long, with the body of 
nearly equal breadth throughout (Fig. 224). They have sharp pro- 
jecting mandibles ; and the caudal end of the body is usually furnished with 
a pair of conical bristly appendages. They live in the same obscure situa- 


COLEOPTERA 


i37 


tions as the adult insects, but are more shy, and are consequently less 
frequently seen. Like the adults, they are predacious. 

Among the more common ground-beetles are the following. 

The searcher, Calosoma scrutator. — This is one of the larger and more 
beautiful of our ground-beetles; it has green or violet wing-covers 
margined with reddish, and the rest of the body is marked with violet- 
blue, gold, green, and copper (Fig. 225). This beetle and the two follow- 
ing have been known to climb trees in search of caterpillars. 


Fig. 225. 


Fig. 226 


Calosoma sycophanta, a common species in Europe, has been intro- 
duced and successfully colonized in New England, as a means of com- 
bating the gipsy-moth and the brown-tail moth. This species is 
somewhat smaller than the preceding, and lacks the reddish band on 
the margins of the elytra. 

The fiery hunter, Calosoma cdlidum, is easily recognized by the rows 
of reddish or copper-colored pits on the wing-covers (Fig. 226). 

The bombardier-beetles,' Bracklnus. — There are many species of 
beetles that have at the hind end of the body little sacs in which is 
secreted a bad-smelling fluid, which is used as a means of defence. These 
beetles spurt this fluid out onto their enemies when attacked. But in 
the case of the bombardier-beetles this fluid changes to a gas, which looks 
like smoke as soon as it comes in contact with the air, and is ejected 
with a sound like that of a tiny pop-gun. When some larger insect tries 
to capture one of these insect-soldiers, and gets very near it, the latter 
fires its little gun into the face of its enemy. The noise astonishes the 
pursuer, and the smoke blinds him. By the time he has recovered from 
his amazement, the little bombardier is at a safe distance. 
These beetles have quite a store of ammunition ; for we have 
often had one pop at us four or five times in succession, 
while we were taking it prisoner. The bombardier-beetles 
belong to the genus Brachinus, of which we have in this 
country twenty-seven species. They are very similar in ap- 
pearance; the head, prothorax, and legs are reddish-yellow, 
and the wing-covers are dark blue, blackish, or greenish-blue (Fig. 227). 

There is a common beetle which resembles the bombardier-beetles 


138 


THE STUDY OF INSECTS 


quite closely in size and color, but which may be distinguished by the 
comb-like form of the tarsal claws; this is Lebia grandis (Fig. 228). 
It has been reported more often than 
any other insect as destroying the Col- 
orado potato-beetle. 

What is perhaps the most common 
type of ground-beetle is illustrated by 
Harpalus caliginosus, which is represented 
natural size in Figure 229. It is of a 
pitchy black color, and is one of the most 
common of our larger species. There are 
one hundred and thirty-six described 
species of Harpalus in this country. Most 
of them are smaller than this one, are 
flattened, and have the prothorax nearly 
square. 

The most common of all ground-bee- 
tles, in the Northeastern States at least, 
is Pcecilus lucublandus. In this species 
(Fig. 230) the narrow, flat margin on each 
side of the prothorax is widened near the hind angle of this segment. 


Fig. 22g. 


Fig. 228. — Lebia gran- 
dis, natural size and en- 
larged 


Fig. 230. 


Family Dytiscid^ 

The Predacious Diving-beetles 

If one will approach quietly a pool of standing water, there may be 
seen oval, flattened beetles hanging head downward, with the tip of the 
abdomen at the surface of the water. Such beetles belong to this family. 
The predacious diving-beetles are usually brownish black and shining, 
but are often marked indefinitely with dull yellow. They can be dis- 
tinguished from the water scavenger-beetles, which they resemble in 
general appearance, by the thread-like form of the antenna?. The hind 
legs are the longest and are fitted for swimming, being flattened and 
fringed with hair. The middle and the hind 
pair of legs are widely separated. In the 
males of certain genera the first three seg- 
ments of the fore tarsi are dilated and form 
a circular disk, upon the under side of which 
are little cup-like suckers (Fig. 231). The 
females of some species exhibit an interesting 
dimorphism in that some of the individuals 
have the elytra furnished with a number of deep furrows (Fig. 232), 
while others of the same species have them smooth. 

The diving-beetles abound in our streams and ponds, but they are 
more often found in standing water than in streams. When at rest they 
float in an inclined position, head downward, with the tip of the hind end 
of the body projecting from the water. The spiracles open on the dorsal 
side of the abdomen beneath the elytra. By lifting the elytra slightly a 
reservoir is formed for air, which the beetle can breathe as it swims 
through the water. When the air becomes impure the beetle rises to the 
surface, forces it out, and takes a fresh supply. 


Fig. 232. 


COLEOPTERA 


i39 


These beetles are very voracious. They destroy not only other in- 
sects, but some of them will attack larger animals, as small fish. When 
kept in aquaria they can be fed upon any kind of meat, raw or cooked. 
They fly from pond to pond, and are often attracted to light at night. 
Many of the species make sounds, both under the water and in the air. 
In some cases this is done by rubbing the abdominal segments upon the 
elytra; in others, by rubbing the hind legs upon a rough spot on the lower 
side of the abdomen. 

The females deposit their eggs singly in punctures in the tissues of 
living plants. The larva? are 
known as water-tigers, be- 
cause of their blood-thirsti- 
ness. They are elongated, 
spindle-form grubs (Fig- 233). fig. 233. 

The head is large, oval or rounded, and flattened; the mandibles are 
large and sickle-shaped; in each there is a slit-like opening near the tip; 
from this opening a canal leads along the inner surface to a basal opening 
on the upper surface, which communicates with the corner of the mouth 
when the mandible is closed. The mandibles are admirably fitted for 
holding prey and at the same time sucking juices from its body. The 
thorax is furnished with six well-developed legs. The abdomen is termi- 
nated by a pair of processes; at the tip of the abdomen there is a pair of 
large spiracles, which the larva protrudes into the air at intervals, in 
order to breathe. 

When a larva is fully grown it leaves the water, burrows into the 
ground, and makes a round cell, within which it undergoes its transforma- 
tions. The pupa state lasts about three weeks in summer ; but the larva? 
that transform in autumn remain in the pupa state all winter. 

This is the largest of the families of water-beetles; more than three 
hundred North American species are known. 

The best way to obtain specimens is to sweep the vegetation growing 
on the bottom of a quiet pool with a dip-net. 

The larger of our common species belong to Cybtster, 
Dythcus (Fig. 234), and allied genera. 

The most common of the diving-beetles which are 
of medium size belong to the genus Acilius. 

There are also common diving-beetles which are of 
about the same size as the preceding, but which have 
the wing-covers marked with numerous very fine trans- 
verse striae; these belong to the genus Colymbetes. 

Of the smaller diving-beetles, measuring less than 
I of an inch in length, many species can be found in 
almost any pond. These represent many genera. 


Fig. 234. — A Dytis- 
cus beetle. 


Family Gyrinid^e 

The II li irl i gig-beetles 

As familiar to the country rover as the gurgling of the brook or the 
flecks of foam on its " golden-braided centre," "or the trailing ferns and 
the rustling rushes on its banks, are these whirligigs on its pools. Around 
and around each other they dart, tracing graceful curves on the water, 


140 


THE STUDY OF INSECTS 


which vanish almost as soon as made. They are social fellows, and are 
almost always found in large numbers, either swimming or resting motion- 
less near together. They rarely dive, except when pursued; but are so 
agile that it is extremely difficult to catch them without a net. Many of 
them when caught exhale a milky fluid having a very disagreeable odor. 
They feed upon small flies, beetles, and other insects that hill into the 
water, and are furnished with well-developed wings, with which they 
fly from one body of water to another. 

This is one of the most easily-recognized families of the whole 
order Coleoptera. The members of it are oval or elliptical in form 
(Fig. 235), more or less flattened, and usually of a very brilliant 
bluish-black color above, with a bronze metallic lustre. The fore 
legs are very long and rather slender; the middle and hind 
Fig. 235- legs are short, broad, and very much flattened. These insects 
are remarkable for having the eyes completely divided by the margin of 
the head, so that they appear to have four eyes — a pair upon the upper 
surface of the head with which to look into the air, and a pair upon the 
under side for looking into the water. The antenna? are very short and 
peculiar in form. The third segment is enlarged, so as to resemble an ear- 
like appendage, and the following ones form a short spindle-shaped 
mass. The}* are inserted in little cavities in front of the eyes. 
The eggs of these insects are small, of cylindrical form, and 
are placed end to end in parallel rows upon the leaves of aquatic 
plants. The larvae (Fig. 236) are long, narrow, and much flat- 
tened. Each abdominal segment is furnished with a pair of 
tracheal gills, and there is an additional pair at the caudal end 
of the bod}-. The elongated form of the body and the con- 
spicuous tracheal gills cause these larva? to resemble small cen- 
tipedes. When a larva is full-grown it leaves the water and 
spins a gray, paper-like cocoon attached to some object near the 
water. The pupa state of those species in which it has been ob- 
served lasts about a month. 

The family is a small one. At present only forty-one North American 
species are known. These represent three genera. The genus Gyretes is 
distinguished by having the last ventral segment of the abdomen elon- 
gated and conical. It is represented by two species. In the other two 
genera the last ventral segment is flattened and rounded at the tip. In 
Dineutus the scutellum is invisible; there are thirteen species of this 
genus. In Gyrinus the scutellum is visible; of this genus we have twenty- 
six species. 


THE HERBIVOROUS BEETLES 

Suborder Polyphaga * 

In the suborder Polyphaga the ventral 
part of the first segment of the abdomen 
is visible for its entire breadth (Fig. 237); 
the first three ventral segments are im- 
movably united (except in the Cupesida?), 
and the notum of the prothorax is not sepa- 
rated from the pleura by distinct sutures. 
polyphagus, eating many kinds of food. 


Fig. 236. 


FlG. 237. — Ventral aspect of part of 
tborax and abdomen of Enchroma giganlea: 
1 j 1, first abdominal segment. 


Polyphaga : 


COLEOPTERA 


141 


The larvae vary greatly in form; some are campodeiform, some are 
scarabeiform, and others are vermiform; in none are the legs more than 
five-jointed, and in none are the legs two-clawed. 

This suborder includes all but the few preceding families of the 
Coleoptera. 


Family Hydrophilid^ 

The Water-scavenger Beetles 

The water-scavenger beetles are common in quiet pools, where they 
may be found swimming through the water, or crawling among the 
plants growing on the bottom. They can be easily taken by sweeping 
such plants with a dip-net. 

They are elongated, elliptical, black beetles, resembling the preda- 
cious diving-beetles in appearance; but they are usually more convex, 
and differ also in having club-shaped antennas and very long palpi. As 
the antennae are usually concealed beneath the head, it often happens 
that the inexperienced student mistakes the long palpi for antennae. 

These beetles are supposed to live chiefly upon the decaying vegeta- 
tion in the water; but a number of species have been known to catch 
and eat living insects. They breathe by carrying a film of air on the 
lower surface of the body. This film gives them a silvery appearance 
when seen from below. They obtain the air by bringing the head to 
the surface of the water and projecting the antennae, which they again 
fold back with a bubble of air when they descend. The female makes a 
case for her eggs out of a hardened silk-like secretion. j^ 

Some species deposit as many as a hundred eggs in one of 
these water-proof packages (Fig. 238). The egg-cases in 
some instances are fastened beneath the leaves of aquatic 
plants; in others they are provided with floats and let 
loose in the water ; and in still other species the cases are 
carried by the mother underneath her body and steadied 
with her hind legs. Frequently some of the young larvae 
devour their companions; in -this way the size of the fam- 
ily is decreased before it escapes from 
the egg-case. Later they live upon insects that fall 
into the water, and upon snails. These larvae re- 
semble somewhat those of the Dytiscidae; but the 
body is much more plump, and the mandibles are 
of moderate size. 

The family Hydrophilidae is represented in North 
America by one hundred and ninety species. The 
largest of our common species is Hydrous trian- 
gularis (Fig. 239). In the genus Hydrous the met- 
asternum is prolonged backward into a spine 
between the hind legs, and the sternum of the protho- 
rax bears a deep furrow. 

Next in size to Hydrous are several species of 
Hydrophilus. In this genus the metasternum is 
prolonged somewhat, but does not form a long, sharp spine as in Hydrous 
and the sternum of the prothorax bears a keel-shaped projection. Our 


M 


:• '.'< 


^ 


'' /" 


,!i 


w 


J ' V 


Fig. 2,38. 


i 4 2 THE STUDY OF INSECTS 

most common species is Hydrophilus obtusdtus; this measures about f of 
an inch in length. 

Some of the smaller species of this family are not aquatic, but live 
in moist earth and in the dung of cattle, where, it is said, they feed on 
dipterous larvae. 

Family Silphid^e 

The Carrion-beetles 

The carrion-beetles are mostly of medium or large size, many species 
attaining the length of if inches while the smaller species of the more 
typical genera are nearly \ inch in length; some members of the fam- 
ily, however, are minute. The segments near the tip of the antennae 
are usually enlarged so as to form a compact club, which is neither comb- 
like nor composed of thin movable plates; sometimes the antennas are 
nearly filiform. 

These insects usually feed upon decaying animal matter; some, how- 
ever, feed upon fungi; some on vegetables; and a few species have been 
known to be predacious when pressed by hunger, destroying living snails 
and insects, even members of their own species; while a few occur only 
in the nests of ants. 

It is easy to obtain specimens of these insects by placing pieces of 
meat or small dead animals in the fields and examining them daily. 
There are several other families of beetles the members of which can be 
attracted in this way. 

The larvae also live upon decaying flesh and 
are found in the same situations as the adults. 

We have in this country more than one hundred 
species of this family. Our larger and more famil- 
iar species represent two genera, Necrophorus and 
SUpha. 

The burying-beetles, Necrophorus. — To this 
genus belong the larger members of the family. 
The body is very stout, almost cylindrical (Fig. 
240). Our common species have a reddish spot on 
each end of each wing-cover; these spots are often 
so large that they appear as two transverse bands. 
In some species the prothorax and the head are 
FlG - 2 4°- also marked with red. 

These insects are called burying-beetles because they bury carrion. 
When a pair of these beetles discover a dead bird, mouse, or other small 
animal, they dig beneath it. removing the earth so as to allow the carrion 
to settle into the ground. This they will continue until the object is 
below the surface of the ground. Then they cover it with earth, and 
finally the female digs down to it and lays her eggs upon it. The larvae 
that hatch from these eggs feed upon the food thus provided for them. 
There are many accounts of exhibitions of remarkable strength and sa- 
gacity by burying-beetles. A pair of these insects have been known to 
roll a large dead rat several feet in order to get it upon a suitable spot 
for burying. 


COLEOPTERA 

The members of the genus Sttpha are very much flattened (F 
The prothorax is round in outline, with very thin edges which 
the wing-covers somewhat. The body is not nearly as stout 
as that of a burying-beetle, being fitted for creeping under 
dead animals instead of for performing deeds requiring great 
strength. Silpha bituberosa, which is known as the spinach 
carrion-beetle, feeds on spinach, beets, and other plants, in 
the West. 

In some of the minute members of this family the body 
is nearly hemispherical. 


143 

ig. 241). 
overlap 


Fig. 242. 


Family Staphylinid^ 

The Rove-beetles 

The rove-beetles are very common about decaying animal matter, 
and are often found upon the ground, under stones or other objects. 
They are mostly very small insects; a few species, however, are of larger 
size, measuring \ inch or more in length. Their appear- 
ance is very characteristic, the body being long and slender, 
and the wing-covers very short (Fig. 242). The wings, 
however, are fully developed, often exceeding the abdomen 
in length ; when not in use the wings are folded beneath the 
short wing-covers. The abdominal segments are freely 
movable. 

It is interesting to watch one of these insects fold its 
wings; frequently they find it necessary to make use of the 
tip of the abdomen or of one of the legs in order to get the 
wings folded beneath the wing-covers. 

The rove-beetles can run quite swiftly; and they have the curious 
habit, when disturbed, of raising the tip of the abdomen in a threatening 
manner, as if they could sting. As some of the larger species resemble 
wasps somewhat in the form of the body, these threatening motions are 
often as effective as if the creatures really had a sting. William Becbe 
states (Atlantic Monthly, October, 1919) that when some rove-beetles 
were attacked by ants they raised their tails and ejected a drop or two 
of a repellent fluid which drove the ants away. This observation indi- 
cates the probable explanation of the actions of these beetles when dis- 
turbed. 

As these insects feed upon decaying animal and vegetable matter, 
they should be classed as beneficial. The larvas resemble the adults 
in the form of the body and are found in similar situations, about decay- 
ing animal and vegetable matter, beneath bark and in fungi. Some 
species are guests in the nests of ants, and others in the nests of termites. 
Nearly three thousand North American species of rove-beetles have 
been described. The great majority are small and exceedingly difficult to 
determine. Among the large species that are common are the following. 
Creophilus maxillosus. — This species varies from \ an inch to nearly 
an inch in length. It is of a shining black color, spotted with patches of 
fine gray hairs. There is a conspicuous band of these across the middle 
of the wing-covers, and another on the second and third abdominal seg- 


i44 THE STUDY OF INSECTS 

ments; this abdominal band is best marked on the lower side of the 
body. 

Staphylinus maculosus is a larger species, which often measures fully 
an inch in length. It is densely punctured, and of a dull brown color, 
with the scutellum black, and a row of obscure, square, blackish spots 
along the middle of the abdomen. 

Staph yllii us vulpinus resembles the preceding somewhat, but it has a 
pair of bright yellow spots at the base of each abdominal segment. 

Ontholestes cingulatus is of about the same size as the preceding. It 
is brown, speckled with brownish-black spots, and the tip of its abdomen 
is clothed with golden hairs. 

Family Lampyrid^e 

The Firefly Family 

During some warm, moist evening early in our northern June we are 
startled to see here and there a tiny meteor shoot out of the darkness 
near at hand, and we suddenly realize that summer is close upon us, 
heralded by her mysterious messengers, the fireflies. A week or two later 
these little torch-bearers appear in full force, and the gloom that over- 
hangs marshes and wet meadows, the dusk that shrouds the banks of 
streams and ponds, the darkness that haunts the borders of forests, are 
illumined with myriads of flashes as these silent, winged hosts move 
hither and thither under the cover of the night. 

The fireflies are soft-bodied beetles of medium or small size, with 
slender, usually eleven-jointed, saw-like antennae. The prothorax is 
expanded into a thin projecting margin, which in most cases 
completely covers the head (Fig. 243). The wing-covers are 
rather soft, and never strongly embrace the sides of the abdo- 
men, as with most other beetles. 

The fireflies are nocturnal insects and are sluggish by day. 

fig" 243. The property of emitting light is possessed by adults of both 

sexes and by larvae. The latter and the wingless females of 

certain species are known as glow-worms. The light-organs of the winged 

adults are situated on the lower side of one or more of the abdominal 

segments ; but they are lacking in some genera. 

There have been many speculations as to the usefulness of the light- 
producing power of various organisms to the organisms themselves; and 
as regards many of these photogenic creatures no definite conclusions 
have been reached. But there is considerable evidence to show that in 
the case of adult lampyrids it serves to enable these insects to find their 
mates. It has been found that females enclosed in a perforated opaque 
box do not attract males, while those enclosed in a glass vial do; thus 
showing that it is the light emitted by the female, and not its odor, that 
attracts the male. It has also been shown that in some cases at least 
there are specific differences in the method of flashing which enables the 
insects to distinguish at a distance their proper mates. 


COLEOPTERA 145 

Family Cantharidae 

The Soldier-beetles and others 

The family Cantharidae includes those genera that were formerly 
included in the family Lampyridse as the subfamily Telephorinas. 

The application of the name Cantharidae to this family is the result 
of one of those unfortunate changes in generic names rendered necessary 
by our code of nomenclature. In this case the change is especially un- 
fortunate, as the generic name Cantharis has been commonly applied to 
certain blister-beetles and is used in that sense in many medical works 
and in most text-books of entomology. The change is sure to result in 
much confusion. 

The most common members of this family are the soldier-beetles, 
Chauliognathus. These are very abundant in late summer and autumn 
on various flowers, but especially on those of goldenrod. The most com- 
mon species in the East are the Pennsylvania 
soldier-beetle, Chauliognathus pennsylvanicus, 
which is yellow, with a black spot in the mid- 
dle of the prothorax and one near the tip of 
each wing-cover (Fig. 244); and the margined 
soldier-beetle, C. margindtus. This species 
(Fig. 245) can be distinguished from the for- 
mer by the head and lower parts of the 
femora being orange. The beetles of this genus FlG ' 245 ' 

are remarkable for having an extensible, fleshy filament attached to each 
maxilla. These filaments are probably used in collecting pollen and 
nectar from flowers. 

This family is represented in our fauna by nine genera which include 
more than one hundred and fifty species. 

Family Meloid^e 
■The Blister-beetles 

The blister-beetles are of medium or large size. The body is com- 
paratively soft; the head is broad, vertical, and abruptly narrowed into 
a neck; the prothorax is narrower than the wing-covers, which are soft 
and flexible; the legs are long and slender; the hind tarsi are four- 
jointed, and the fore and middle tarsi are five-jointed. 

These beetles are found on foliage and on flowers, on which they feed 
in the adult state; some of the species are very common on goldenrod in 
the autumn; and several species feed on the leaves of potato. 

The blister-beetles are so called because they are used for making 
blister-plasters. The beetles are killed, dried, and pulverized, and the 
powder thus obtained is made into a paste, which when applied to the 
skin produces a blister. The species most commonly used is a European 
one, commonly known as the Spanish-fly; but our American species 
possess the same blistering property. 

The transformations of blister-beetles are remarkable; not only do 
these insects undergo wonderful changes in form, but the number of 
these changes is greater than is usual with insects. On this account their 
mode of development is termed hyper metamorphosis. 


146 


THE STUDY OF INSECTS 


The beetles lay their eggs in the ground. The newly hatched larva 
is active, running about in search of its food, which consists, in some 
species, of the eggs of locusts, in others of the egg and honey of some 
solitary bee. 

In the case of those species that live in the nests of bees the larva 
climbs a plant, and remains near a flower till it has a chance to seize 
hold of a bee visiting the flower. The larva clings to the bee until she 
goes to her nest, then, letting go of the bee, it remains in the cell and is 
shut up there with the egg of the bee and the store of food which the 
bee provides for her young. The beetle larva then devours the egg; after 
which it moults and undergoes a change of form, becoming a clumsy 
creature, which feeds upon the honey. Several other changes in form 
occur before the beetle reaches the adult stage. 

The wonderful instinct by which the larva? of these blister-beetles find 
their way to the nests of solitary bees has not yet reached perfection ; for 
many of the larvae attach themselves to flies, wasps, honey-bees, and other 
flower-visiting insects, and merely gain useless transportation thereby. 

The life cycle of the striped blister-beetle, Epicauta vittata, illustrates 
the hypermetamorphosis through which the blister-beetles pass. The 
female deposits her eggs in a mass of a hundred or more in a hole in the 
soil. They hatch into very active larvae each of which is known as a 
triungulin. The triungulin has long legs and runs about in search of 
eggs of grasshoppers. It feeds ravenously on the eggs and in about eight 
days molts to the second stage, called the caraboid stage, because it then 
resembles the larva of a carabid beetle. In another week it molts and 
assumes the appearance of a scarabaeid larva and is therefore called the 
scarabasidoid stage of the second larva. In a short time it molts again to 
the ultimate stage of the second larva. In about ten days more it molts 
again and becomes the pseudo-pupa or the coarctate larva. This form 
usually hibernates and in the spring transforms to the third larval stage. 
In a few days this larva transforms to the pupa in an earthen cell and in 
five or six days the pupa transforms to the adult beetle (Fig. 246). 


f\. 


FlO, 246. — liypermctamorphosis of the striped blister-beetle; A, triungulin; B, caraboid stage; D, scara- 
baeidoid stage; C, coarctate larva; E, pupa; F, adult beetle. 


COLEOPTERA 


i47 


More than two hundred species of blister-beetles have been found in 
this country. Our most common species in the East belong to the genus 
Epicauta. These insects feed in the adult state on the leaves of various 
plants, but especially those of potato, and upon the pollen of goldenrod; 
the larvae, so far as is known, are parasitic in the egg-pods of 
locusts. In addition to Epicauta vittata, discussed above, our 
more common species are the Pennsylvania blister-beetle, 
Epicauta pennsylvdnica, which is of a uniform black color 
(Fig. 247); and Epicauta cinerea, which is sometimes clothed 
throughout with an ash-colored pubescence, and sometimes 
the wing-covers are black, except a narrow gray margin; 
the two varieties were formerly considered distinct species; 
the first is commonly known as the gray blister-beetle, the 
last as the margined blister-beetle. 

The beetles of the genus Melee present an exception to 
the characters of the Coleoptera in that the wing-covers, 
instead of meeting in a straight line down the back, overlap 
at the base (Fig. 248). These wing-covers are short, and 
the hind wings are lacking. These beetles are called oil- 
beetles in England, on account of the yellowish liquid 
which oozes from their joints when they are handled. 
Our most common species is the buttercup oil-beetle, 
Melos angusticollis . It is found in meadows and pastures 
feeding on the leaves of various species of buttercups. 


Fig. 247. 


Fig. 248. 


Fig. 249. 


Family Elaterid^e 
The Click-beetles or Elaters 

There is hardly a country child that has not been entertained by the 
acrobatic performances of the long, tidy-appearing beetles called snap- 
ping-bugs, click-beetles, or skip-jacks (Fig. 249). Touch one of \/^ 
them and it at once curls up its legs, and drops as if shot; it 
usually lands on its back, and lies there for a time as if dead. 
Suddenly there is a click, and the insect pops up into the air 
several inches. If it comes down on its back, it tries again and 
again until it succeeds in striking on its feet, and then it 
runs off. 

Our common species of click-beetles are mostly small or of medium 
size, ranging from -fa to f of an inch in length. A few species are 

> — m- , <*■ larger, some reaching the length of nearly 2 inches. The 

^jr' \(^/ majority of the species are of a uniform brownish color; 
/8k Hv s< line are bl ac k " r grayish, and some are conspicuously 

^^ >/liJ\V s P°tted (Fig. 250). The body is elongated, somewhat flat- 
/ /^Byy tened, and tapers more or less toward each end; the 
antennae are moderately elongated and more or less ser- 
rate; the first and second abdominal segments are not 
grown together on the ventral side ; and the hind coxae are 
each furnished with a groove for the reception of the femur. 
Adult elaters are found on leaves and flowers, and are exclusively 
phytophagous; the larvae live in various situations; most of them are 
phytophagous, but some species are carnivorous. 


Fig. 250. — A click- 
beetle, Aeolus dorsalis, 
natural size and en- 
larged. 


t 4 8 THE STUDY OF INSECTS 

The larvae are long, narrow, worm-like creatures, very even in width, 
with a very hard cuticula, and are brownish or yellowish in color (Fig. 

251). They are commonly known as wire- 
\v< >rms, a name suggested by the form 
and hardness of the body. 

Some wireworms live under the bark 
of trees and in rotten wood; but many 
of them live in the ground, and feed on 
seeds and the roots of grass and grain. In fact there is hardly a culti- 
vated plant that they do not infest, and, working as they do beneath the 
surface of the ground, it is extremely difficult to destroy them. They 
are very apt to attack the plants at the most susceptible period of 
their growth, before they have attained sufficient size and strength to 
withstand the attack; and often seed is destroyed before it is germinated. 
There is a vast number of species of click-beetles; more than five 
hundred have been described from North America alone. It is quite 
difficult to separate the closely allied species, as there is but little varia- 
tion in shape and color. 

The corn wireworm beetle, Melanotics communis, is a graceful brown 
beetle about \ an inch in length (Fig. 249). The larva, or wireworm is 


about 1 j inches in length, cylindrical and shining brown 
extends over a period of five years in most cases. 

The wheat wireworm beetle, Agriotes mancus, is a 
small brown beetle about § of an inch in length. The 
larva, or wireworm is about one inch long and as large 
as the lead in a pencil. The life cycle extends over a 
period of three years. 

The eyed elater, Alaus oculatus. — Although most 
of our click-beetles are of moderate size, we have a 
few species that are large. The most common of 
these is the eyed elater. This is the great pepper- 
and-salt-colored beetle that has two large, black, vel- 
vety, eye-like spots on the pro thorax (Fig. 252). These 
are not its eyes, however. The true eyes are situated 
one on each side of the head near the base of the an- 
tenna. This insect varies greatly in size, some individ- 
uals being not more than half as large as others. 
The larger larvae are about two and a half inches long 
fifths of an inch wide across the middle of the bodv. 


The life cycle 


Fig. 252. 


and nearly two- 
They are carniv- 


orous and are often found in the trunks of old apple-trees. 


Family Buprestids 
The Metallic Wood-borers or Buprestids 

The buprestids resemble the click-beetles somewhat in form, being 
rather long and narrow; but they are easily recognized by their metallic 
coloring. Their bodies are hard and inflexible, and usually appear as if 
made of bronze; but some species exhibit the brightest of metallic colors. 
The antennae are serrate; the first and second abdominal segments are 
grown together on the ventral side; and these beetles do not have the 
power of springing when placed on the back. 


COLEOPTERA 


149 


The adults are found upon flowers and upon the bark of trees, basking 
in the hot sunshine. Some of them fly very rapidly, with a loud buzzing 
noise; and some drop to the ground when disturbed, and feign death. 

Most of the larvae are borers, feeding beneath bark or within solid 
wood. In such species the body is of a very characteristic form, which 
is commonly designated as " flat-headed." The flattened portion, how- 
ever, is composed largely of the segments immediately following the head. 
The first thoracic segment is very wide and flat; the next two or three 
segments are also flattened, but are successively smaller; while the rest 
of the body is quite narrow and cylindrical. These " flat-headed" larvae 
are legless, and have been compared to tadpoles on account of their 
form. Their burrows are flattened, corresponding with the shape of the 
larger part of the body. In some of the smaller species the larvas are 
cylindrical, and are furnished with three pairs of legs. These are leaf- 
miners; and in the adult state the body is much shorter than in the 
more typical species. 

This family is represented in our fauna by nearly three hundred 
species; among the more important of those that infest cultivated plants 
are the following. 

The Virginian buprestid, Chalcophora virginica. — ■ This is the largest 
of our common buprestids (Fig. 253). It is 
copper-colored, often almost black, and has 
its upper surface roughened by irregular, 
lengthwise furrows. This beetle appears late 
in spring in the vicinity of pine-trees. The 
larvae bore in the wood of pine, and are often 
very injurious. 

Dicerca divaricdta is f of an inch or more 
in length, copper-colored or brassy above, with 
the wing-covers marked with square, elevated, black spots. 
The wing-covers taper very much behind, and are separated at the 
tips (Fig. 254). The larva bores in peach, cherry, beech, and maple. 

flat-headed apple-tree borer, Chrysobothris femorata. — This is 
one of the most injurious of all buprestids. The adult (Fig. 
255) is about I an inch long, and is very dark green above, with 
bronze reflections, especially in the furrows of the wing-covers. 
It appears during June and July, and lays its eggsupon the trunk and 
limbs of apple, peach, oak, and other trees. The larvae at first 
bore into the bark and sap-wood, and later into the solid 
wood. The transformations are completed in one year, 
red-necked agrilus, Agrilus ruficollis. — This beetle is 
of an inch long (Fig. 256). Its body is narrow and nearly 
cylindrical. The head is of a dark bronze color, the prothorax of 
a beautiful coppery bronze, and the wing-covers black. The larva 
bores in the stems of raspberry and blackberry, causing a large FlG - 256 - 
swelling, known as the raspberry gouty-gall. These galls should be collected 
and burned in early spring. 

The bronze birch-borer, Agrilus anxius, is a greenish-bronze beetle about 
^ of an inch long which appears in June and July and deposits its egg in 
cracks of the bark of the white birch and of other birches. The whitish, 
slender larvae bore through the sapwood and inner bark completely girdling 
the branches and trunk and usually killing the trees. 


Fig. 254. 


Fig. 253. 


The 


Fig. 255. 

The 
about x 


150 THE STUDY OF INSECTS 

Family Dermestid.-e 
The Dermestids 

There are several families of small beetles that feed on decaying 
matter, or on skins, furs, and dried animal substances. The most im- 
portant of these is the Dermestidae, as several species belonging to this 
family destroy household stores or goods. 

The dermestids can be distinguished from most of the other beetles 
with similar habits by the fact that the wing-covers completely cover the 
abdomen. They are chiefly small beetles, although one of the common 
species measures ^ of an inch in length. They are usually oval, plump 
beetles, with pale gray or brown markings, which are formed of minute 
scales, which can be rubbed off. These beetles have the habit of pretend- 
ing that they are dead when they are disturbed; they will roll over on 
their backs with their legs meekly folded and lie still for a long period. 

The larvae do much more damage than the adults. They are active, 
and are clothed with long hairs. These hairs are covered throughout 
their entire length with microscopic barbs. 

This family is represented in our fauna by about one hundred thirty 
species; the following are some of the more important to these. 

The larder-beetle, Dermestes lardarius. — This pest of the larder is 
the most common of the larger members of this family. It measures 
about \ of an inch in length, and is black except the basal half of its 
wing-covers, which are pale buff or brownish-yellow. This lighter 
portion is usually crossed by a band of black spots, three on 
K each wing-cover (Fig. 257). The larva feeds on dead animal 
[^ matter, as meat, skins, feathers, and cheese. It is often a 
serious pest where bacon or ham is stored. When full-grown it 
is about \ an inch in length, dark brown above, whitish below, 
and rather thickly covered with long, brown hairs. It is said that these 
insects can be attracted by baits of old cheese, from which they may be 
gathered and destroyed. 

The carpet-beetle, Anthrenus scrophularice. — This is a well-known 
household pest. It is an introduced European insect, which was first 
recognized as a serious pest in this country about 1874. It feeds in its 
larval state on carpets, woollens, furs, and feathers; and for a consider- 
able period was exceedingly destructive. The larva is well known to 
many housekeepers as the buffalo-moth. It is a short, fat grub, about 
I of an inch in length when full-grown, and densely clothed with dark 
brown hairs. It lives in the cracks of floors, near the edges of rooms, 
and beneath furniture, where it eats holes in the carpet. It also enters 
wardrobes and destroys clothing. The adult is a pretty little beetle 
which may be found in infested houses, in the spring, on the ceilings 
and windows. It measures from T *2 to \ of an inch in length and is 
clothed with black, white, and brick-red scales. There is a whitish spot 
on each side of the prothorax, and three irregular, whitish spots on the 
outer margin of each wing-cover; along the suture where the two wing- 
covers meet there is a band of brick-red scales, which is widened in 
several places. It is worth while to learn to know this beetle; for a 
lady-bug which often winters in our houses is frequently mistaken for it. 


COLEOPTERA 151 

The carpet-beetle in its adult state feeds on the pollen of flowers. Some- 
times it abounds on the blossoms of currant, cherry, and other fruits. 

The museum pests, Anthrenus verbdsci and Anthrenus musebrwm. — 
There are two minute species of this family that are a constant source of 
annoyance to those having collections of insects. The adult beetles 
measure from -^ to £ of an inch in length, and are very convex. They 
deposit their eggs on specimens in our collections; and the larvae feed 
upon the specimens, often destroying them. In order to preserve a 
collection of insects it is necessary that they should be kept in tight cases, 
so that these pests cannot gain access to them. Specimens should not be 
left exposed except when in use. And the entire collection should be 
carefully examined at least once a month. The injury is done by the 
larvae, which are small, plump, hairy grubs. Their presence is indicated 
by a fine dust that falls on to the bottom of the case from the infested 
specimens. These larvas can be destroyed by pouring a small quantity 
of carbon bisulphide into the case, and keeping it tightly closed for a 
day or two. Benzine poured on a bit of cotton in the box will cause the 
pests to leave the specimens, when they may be taken from the box and 
destroyed. But we have found carbon bisulphide the better agent for 
the destruction of these pests. 

Family Tenebrionid^e 

The Darkling Beetles 

The darkling beetles are nearly all of a uniform black color, although 
some are gray, and a few are marked with bright colors. The different 
species vary greatly in size and in the form of the body. The hind tarsi 
are four-jointed, and the fore and middle tarsi are five-jointed. 

These insects occur chiefly in dry and warm regions. Thus while 
we have comparatively few species in the northeastern United States, 
there are many in the Southwest. Most of the species feed on dry 
vegetable matter, and often on that which is partially decomposed; 
some live in dung, some in dead animal matter, others in fungi, and a 
few prey upon larvae. More than eleven hundred species occur in this 
country. The three following will serve to illustrate the variations in 
form and habits. 

The meal-worm, Tenebrio mblitor. — This is a well-known pest in 
granaries and mills. The larva is a hard waxy yellow, cylindrical " worm, " 
which measures when full-grown 1 inch or more in length, 
and closely resembles a wireworm; it feeds on flour and meal. 
The beetle is black and about f of an inch in length, (Fig. 258). 
The larvae and pupae are used for bird-food and are grown in 
quantity by bird-supply houses. 

The forked fungus-beetle, Bolitotherus cornutus, 
is common in the northeastern United States and 
in Canada about the large toadstools which grow 
on the sides of trees. The surface of the body and wing- 
covers is very rough, and the pro thorax bears two prominent 
horns (Fig. 2^0). The larva lives within the fungi referred to 

Fig. 250. \ t> jvt o 

above. 
The pinacate-bugs. — Several species of Elebdes are abundant on the 


152 


THE STUDY OF INSECTS 


Fig. 260. 


Pacific Coast, where they are found under stones and pieces 
of wood lying on the gr< lund. They are apt to congregate in 
large numbers under a single shelter, and are clumsy in 
their movements. They defend themselves when dis- 
turbed by elevating the hinder part of the body and 
discharging an oily fluid from it. They present an 
absurd appearance, walking off clumsily, and carry- 
ing the hind end of the body as high as possible. 
The most common species are large, smooth, club- 
shaped beetles (Fig. 260), and are commonly known 
as pinacate-bugs. These beetles and those belonging 
to several closely allied genera lack hind wings. 


Family Cucujid^e 
The Cucujids 

The insects of this family are very flat and usually of an elongate 
form; most of the species are brown, but some are of a bright red color. 
As a rule they are found under bark and are believed to be carnivorous 
both in the larval and adult states; but some feed in grain. There are 
nearly one hundred species in our fauna. 

The most important member of this family is the corn silvanus, 
Oryzaphilus sur in amen sis, which is one of the small beetles that infest 
stored grain. This species is readily distinguished from other small 
beetles with similar habits by its flattened form and the saw-like edges 
of the prothorax. Besides grain it often infests dried fruits and other 
stores. It measures from -^ to \ of an inch in length. The larva as well 
as the adult feeds on grain. It differs from the larva of the granary- 
weevil (Sitophihts) in the more elongate form of its body and in the 
possession of three pairs of legs. 


Family Coccinellid^e 

The Lady-bugs 

These insects are well-known to nearly everyone under the popular 
name given above. They are more or less nearly hemispherical, generally 
red or yellow, with black spots, or black, with white, red, or yel- 
low spots. 

The larva? occur running about on foliage; they are of- 
ten spotted, with bright colors and clothed with warts or 
with spines (Fig. 261). When ready to change to a pupa the 
larva fastens itself by its tail to any convenient object, and 
the skin splits open on the back. Sometimes the pupa 
state is passed within this split skin, and sometimes the skin is 
forced back and remains in a little wad about the tail (Fig. 
262). 

With very few exceptions, the lady-bugs are predacious, 
both in the larval and adult states. They feed upon small 
insects and upon the eggs of larger species. The larva? of certain species 


Fig. 261. 


Fig. 262. 


COLEOPTERA 


i53 


are known as " niggers " by hop-growers, and are greatly prized by them; 
for they are very destructive to the hop-louse. On the Pacific Coast lady- 
bugs are well-known as the most beneficial of all insects to the fruit-growers. 
In addition to the native species found there, several species have been 
introduced as a means of combating scale-insects. One of these, 
Rodolia cardinalis, has proved of very great value in subduing the 
cottony-cushion scale (Icerya purchasi). This lady-bug was introduced 
from Australia. 

A very common one is the two-spotted lady-bug, Adalia bipunctdta. 
This species is reddish-yellow above, with the middle of the prothorax 
black, and with a black spot on each wing-cover. It frequently passes 
the winter in our dwellings, and is found on the walls and windows in 
early spring. Under such circumstances it is often mistaken for the 
carpet-beetle, and, unfortunately, destroyed. (See Plate I,Figure3). 

The nine-spotted lady-bug, Coccinella novemnotdta, has yellowish 
wing-covers, with four black spots on each, in addition to a 
common spot just back of the scutellum (Fig. 263). fig. 263. 

There are two " black sheep " in this family of lady-bugs, namely, 
the squash lady-bug, Epildchna boredlis and the bean lady-bug, Epilachna 
corrupta. The adults and larvae of both of these species are herbivorous 
and injurious, especially those of the latter. The bean lady-bug from its 
former home in the south-western states, suddenly appeared in Alabama 
in 1 919 and has now spread over most of the eastern United States and 
into Canada. It is pale yellowish to orange-brown and from \ to § of an 
inch in length. Each wing-cover has eight black spots arranged in three 
transverse rows. The larva? and adults feed on bean plants and are very 
destructive. 


Fig. 264. 


The squash lady-bug lives on various cucurbitacecus plants but it 
prefers the squash and often becomes destructive (Fig. 264). 


i54 THE STUDY OF INSECTS 

Family Scarab^id^e 
The Scarabceids or Lamellicorn Beetles 

This very large family is represented in our fauna by nearly one thou- 
sand species, and includes beetles that exhibit a wide range of variation 
in size, form, and habits. They are mostly short, stout-bodied beetles, 
of which the well-known June-bugs or May-beetles represent the most 
familiar type. The most useful character for distinguishing these insects 
is the lamellate form of the club of the antennae, the segments constitut- 
ing it being greatly flattened, and capable of being brought close to- 
gether. It is this character that suggests the name lamellicorn beetles. 

According to their habits, the members of this family can be sep- 
arated into two well-marked groups — the scavengers and the leaf- 
chafers. 

THE LAMELLICORN SCAVENGERS 

The lamellicorn scavengers in both the larval and adult states feed 
upon decaying vegetable matter. Nearly all the species live in dung, 
chiefly that of horses and cows; but a few species feed upon fungi. The 
following are the more common representatives of this division. 

The tumble-bugs. — These are the most familiar of all dung-beetles, 
for their peculiar habits have attracted much attention from the earliest 
times. They are of rounded form, and the wing-covers are shortened so 
as to expose the tip of the abdomen. They are generally black, but 
some are colored with rich metallic hues. They vary greatly in size. 

The name tumble-bug refers to the habit which many species exhibit 
of forming round balls of dung, which they roll long distances and then 
bury. They often work in pairs and it was formerly believed that such a 
pair was a male and a female working together to make provision for 
their progeny; but Fabre found by dissecting the beetles that the two 
members of a pair often proved to belong to the same sex; and concluded 
that the eager fellow- worker, under the deceitful pretense of lending a 
helping hand, nurses the scheme of purloining the ball at the first oppor- 
tunity. 

According to the observations of Fabre, the balls made early in the 
year are devoured by the beetles, which bury themselves with them and 
feed upon them. Later, other balls are made and buried, upon each of 
which an egg is laid. The larva hatching from this egg feeds upon the 
ball of dung, and when full-grown transforms within the cavity in which 
the ball was placed. 

This strange habit of rolling these balls has occasioned much specula- 
tion as to its object, and has been the source of many superstitions, 
especially in ancient times. The only reasonable theory that we have 
met is that, as many predacious insects frequent the masses of dung from 
which the balls are obtained, in order to prey upon the larvae which live 
there, the more intelligent tumble-bugs remove the food for their larva? 
to a safe distance. 

The most noted member of this group of genera is the sacred beetle 
of the Egyptians, Ateuchus sdcer. This insect was held in high veneration 
by this ancient people. It was placed by them in the tombs with their 


COLEOPTERA 


i5S 


dead; its picture was painted on sarcophagi, and its image was carved 
in stone and precious gems. These sculptured beetles can be found in 
almost any collection of Egyptian antiquities. 

From the habits and structure of this scarabseid the Egyptians 
evolved a remarkable symbolism. The ball, which the beetles were sup- 
posed to roll from sunrise to sunset, represented the earth; 
the beetle itself personified the sun, because of the sharp pro- 
jections on its head, which extend out like rays of light; 
while the thirty segments of its six tarsi represented the 
days of the month. All individuals of this species were 
thought to be males, and a race of males symbolized a 
race of warriors. This latter superstition was carried over 
to Rome and the Roman soldiers wore images of the sacred t ^^^ 6s '~ Cm ' 
beetle set in rings. 

Our common tumble-bugs are distributed among three genera: 
Cdnthon (Fig. 265), Copris, and Phanceus. 


Fig. 266. 


THE LAMELLICORN LEAF-CHAFERS 

The leaf-chafers are herbivorous insects which in the adult state 
usually feed upon the leaves of trees, but many of the species devour the 

pollen and petals of flowers. In the larval 
state some of these insects are found in rot- 
ten wood; others live in the ground, where 
they feed upon the roots of grass and other 
plants. These larvse are thick, fleshy grubs, 
with well-developed legs (Fig. 266). The 
caudal segments of the abdomen are very 
large, and appear black on account of the 
large amount of dirt in the intestine. The 
body is strongly' curved, so that the larvae 
can crawl only with great difficulty; when 
in the ground they usually lie on their backs. 
The following groups include the more 
important representatives of this division. 

I. The May-beetles or June-bugs. — During the warm evenings of 
May and June we throw open our windows so that we may feel the 
refreshing coolness of the night air and the inspiration of the new sum- 
mer. _ Suddenly, as we sit working or reading, our peace is disturbed by a 
buzzing object which whirls above us. Then comes a sharp thud and 
silence. A little later the scratching of six pairs of tiny claws tells us the 
whereabouts of the intruder. But so familiar are we with his kind that 
we need_ not look to know how he appears, the mahogany-brown blun- 
derer, with yellowish wings sticking out untidily from under his polished 
wing-covers. 

Although these insects are beetles, and attract our attention each 
year m May, they have received the infelicitous title of June-bugs. They 
are more properly termed May-beetles. 

The May-beetles belong to the genus Phyllophaga, of which we have 
nearly one hundred species. The adults frequently do much injury by 
eating the foliage of trees. In the case of large trees this injury usually 
passes unnoticed; but small trees are often completely defoliated by 


i<6 


THE STUDY OF INSECTS 


Fig. 267. 


them. When troublesome, they can be easily gathered by shaking them 
from trees upon sheets. Figure 267 represents a common species. 

The larvae of the different species of May-beetles are 
commonly classed together under the name " white grubs." 
They are often great pests in meadows and in cultivated 
fields. We have known large strawberry plantations to 
be destroyed by them, and have seen large patches of 
ground in pastures from which the dead sod could be 
rolled as one would roll a carpet from a floor, the roots 
having been all destroyed and the ground just beneath the 
surface finely pulverized by these larvae. No satisfactory 
method of fighting this pest has been discovered as yet. 
If swine be turned into fields infested by white grubs they 
will root them up and feed upon them. We have destroyed great numbers 
of the beetles by the use of trap-lanterns, but many beneficial insects 
were destroyed at the same time. 

II. The rose-bugs. — The common rose-bug, Macrodactylus sub- 
spinosus, is a well-known pest. It is a slender beetle, taper- 
ing before and behind, and measuring f of an inch in length 
(Fig. 268). It is thickly clothed with fine, yellow, scale-like 
hairs, which give it a yellowish color; the legs are long, slender, 
and of a pale red color. These beetles appear in early summer 
and often do great injury to roses and other flowers, and to 
the foliage of various fruit-trees and shrubs. This is a very 
difficult pest to control. The larva- of rose-bugs feed on the roots of 
plants. 

III. The shining leaf-chafers. — These insects resemble the May- 
beetles in form, but can be distinguished from them by the position of 
the hind pair of spiracles, which are visible on the sides below the edges 
of the wing-covers; and they differ from the other leaf-chafers in which 
the spiracles are in this position in that the tarsal claws are of unequal 
size, one claw of each pair being larger than the other. These beetles 
are usually polished, and many of them are of brilliant colors. To this 
family belong the most beautiful beetles known, many appearing as if 
made of burnished gold or silver, or other metal. 

The goldsmith-beetle, Cotalpa lamgera. — This is one of our most 
beautiful species. It measures about one inch in length, 
and is a broad oval in shape. It is of a lemon-yellow 
color above, glittering like burnished gold on the top of 
the head and thorax; the under side of the body is 
copper-colored and thickly covered with whitish wool. 

The spotted pelidnota, Pelidnota punctata. — This bee- 
tle is reddish-brown above, with three black spots on 
each wing-cover and one on each side of the prothorax 
(Fig. 269). The scutellum, base of the head, and entire 
body beneath, are of a deep, bronzed-green color. The 
adult is commonly found feeding on the leaves of grape. 
The larva feeds upon decaying roots and stumps of various trees. 

The Japanese beetle, Popillia japonica. — This is a very serious pest 
which feeds in the adult state on the foliage of many cultivated and wild 
plants, being practically omnivorous, and in the larval state feeds on the 
roots of grasses. It was first observed in this country in a limited area in 


Fig. 269. 


COLEOPTERA 


iS7 


Burlington County, New Jersey, in 191 6, and has since spread into 
Pennsylvania and New York. The adult insect is about the size of the 
Colorado potato-beetle, but slightly longer 
(Fig. 270). The head and thorax are shin- 
ing bronze-green in color, with the wing- 
covers tan or brownish, tinged with green 
on the edges. Along the sides of the abdo- 
men are white spots, and two very distinct 
white spots at the tip of the abdomen below 
the wing-covers. The larva resembles the 
larva? of May-beetles. 

IV. The rhinoceros-beetles. — ■ The name 
rhinoceros-beetles was suggested for this group 
by the fact that in many species the male 
bears a horn on the middle of the head. In 
addition to this horn there may be one or 
more horns on the thorax. These beetles are 
of medium or large size; in fact, the largest beetles known belong to this 
group. As with the flower-beetles, the 
claws of the tarsi are of equal size, but 
the fore coxae are transverse, and not 
prominent. 

One of the largest of our rhinoceros- 
beetles is Dynastes tityrus. This is of 
a greenish-gray color, with scattered 
black spots on the wing-covers, or, if 
only recently transformed, of a uniform 
dark brown. The male (Fig. 271) bears 


Japanese beetle, enlarged 


Fig. 271. 


a prominent horn on the top of the 
head, and a large one and two small 
ones on the prothorax. The female has 
only a tubercle on the head. This in- 
sect is found in the Southern States ; the 
larva lives in rotten wood. In the far 
west there is a closely allied species, 
Dynastes grant it, in which the large 
horn on the thorax is twice as long 
as in D. tityrus. In the West Indies 
there occurs a species, Dynastes hercules, 
which measures 6 inches in length. 

The sugar-cane beetle, Euetheola 
rugiceps, is a serious pest in the cane- 


Fig. 272. 


Y\.H.U\GV\0\_S. 
- The sugar-cane beetle. 


fields of Louisiana, and it sometimes injures corn (Fig. 272). 


i58 


THE STUDY OF INSECTS 


Y. The flower-beetles. — The flower-beetles are so called because many 
o! them are often seen feeding upon pollen and flying from flower to 
flower. These beetles are somewhat flattened, or nearly level on the 
back; the claws of the tarsi are of equal size and the 
tore coxa' are conical and prominent. More than one 
hundred species occur in this country. 

The hermit flower-beetle, Osmoderma eremicola. — 
This is one of the larger of our flower-beetles (Fig. 
273). It is of a deep mahogany-brown color, nearly 
smooth, and highly polished. It is supposed that the 
larva lives on decaying wood in forest trees. 

The genus Euphoria represents well the form of 
the more typical flower-beetles, which are distinguished 
by the margin of each wing-cover having a large, wavy 
indentation near its base, which renders the side 
pieces of the mesothorax visible from above. This 
indentation makes it unnecessary for these insects to 
fig. 273. raise or expand their wing-covers when flving, as 

most beetles do, as they are able to pass the wings out from the sides. 

The bumble flower-beetle, Euphoria inda. — The most 
common of our flower-beetles, at least in the North, is a 
yellowish-brown one, with the wing-covers sprinkled all over 
with small, irregular, black spots (Fig. 274). It is one of the 
first insects to appear in the spring. It flies near the sur- 
face of the ground with a loud humming sound, like that of a 
bumblebee, for which it is often mistaken. During the 
summer months it is not seen; but a new brood appears 
about the middle of September. The adult is a general feeder 
occurring upon flowers, eating the pollen, upon corn-stalks 
and green corn in the milk, sucking the juices, and upon peaches, 
grapes, and apples. Occasionally the ravages are very serious. 

The green June-beetle or "fig-eater, Cotinus nitida. — This species 
extends over the Atlantic slope, and is very common in the South. It is 
a green, velvety insect, measuring about one inch in length. It is some- 
what pointed in front, and usually has the sides of the thorax and elytra 
brownish-yellow. These beetles often fly in great numbers at night, 
making a loud buzzing noise similar to that of the May-beetles. In fact, 
in the South the term June-bug is often applied to this insect. The 
larvae feed upon the vegetable mold of rich soils; sometimes they injure 
growing vegetables by severing the roots and growing stalks; but the 
chief injury is due to the upheaval of the soil around the plants, which 
disturbs the roots; the larvae are also often troublesome on lawns and 
golf greens by making little mounds of earth on the surface. Sometimes 
they leave the ground and crawl from one place to another. When they 
do so, they, strangely enough, crawl upon their backs, making no use of 
their short legs. On one occasion we saw them crawling over the pave- 
ments on the Capitol grounds at Washington in such numbers that 
bushels of _ them were swept up and carted away. The adults frequently 
attack fruit, especially figs, grapes, and peaches. 

A closely related beetle, Cotinus mutabilis, occurs in the Southwest and 
attacks fruits in a similar manner. So far as known, its habits and life his- 
tory arc much like those of the fig-eater. 


Fig. 274. 


COLEOPTERA 


159 


Family Trogid^e 
The Skin-beetles 

This is a small family, which is represented in this country by 
twenty-five species. Until recently these insects were included in the 
preceding family; they can be distinguished from scarabaeids by the fact 
that the epimera of the mesothorax do not extend to the coxae as they do 
in the Scarabaeidae. The members of this family are oblong, convex 
species, in which the surface of the body and wing-covers is usually very 
rough, and covered with a crust of dirt, which is removed with great 
difficulty. They are small or of medium size; our most common species 
measure from \ to \ an inch in length. The abdomen is covered by the 
elytra; the feet are hardly fitted for digging, but the femora of the front 
legs are greatly dilated. 

These beetles feed upon dried, decomposing animal mat- 
ter; many species are found about the refuse of tanneries, 
and upon the hoofs and hair of decaying animals. 

Except a few species found in the far west, all of our 
species belong to the genus Trox (Fig. 275). Fig. 275. 


Family Lucanid^e 

The Stag-beetles 

The stag-beetles are so called on account of their large mandibles 
which in the males of some species are branched like the antlers of a 
stag. They and the members of the following family are distinguished 
by the form of the club of the antennae, which is composed of flattened 
plates; but these plates are not capable of close apposition, as in the 
antennas of the lamellicorn beetles. In the stag-beetles the mentum is 
not emarginate and the ligula is covered by the mentum or is at its apex. 

The adult beetles are found in or beneath 
decaying logs and stumps. Some of them are 
attracted at night to lights. They are said to 
live on honey-dew and the exudations of the 
leaves and bark of trees, for procuring which the 
brushes of their jaws and lips seem to be de- 
signed; but it seems probable that some species, 
at least, feed upon decomposing wood . They lay 
their eggs in crevices of the bark of trees, espe- 
cially near the roots. The larvae feed upon juices 
of wood in various stages of decay. They re- 
semble the well-known larvae of May-beetles. 

The family is a small one ; only thirty North 
American species are now known. 

The common stag-beetle, Lucdnus dama. — 
The most common of our stag-beetles is this spe- 
cies (Fig. 276). It flies by night with a loud buz- 
zing sound, and is often attracted to lights in houses. The larva is a 
large, whitish grub resembling the larvae of the lamellicorn beetles. It is 
found in the trunks and roots of old, partially decayed trees, especially 


Fig. 276. 


i6o 


THE STUDY OF INSECTS 


apple, cherry, willow, and oak. The specimen figured here is a male; 
in the female the mandibles are shorter. 

The giant stag-beetle, Lin amis elafhus, is a large species found in the 
South. It measures from if inches to 2 inches in length, not including 
the mandibles, which in the case of the male are more than half 
as long as the body, and branched like the antlers of a stag. 
The antelope-beetle, Dorcus parallel us. — This beetle is 
somewhat smaller than the species of Lucanus, and differs 
in having the wing-covers marked with longitudinal stria? 
and the teeth on the outside of the fore tibiae much smaller 
(Fig. 277). 

Several species of stag-beetles that are much smaller 
Fie. 277. than Dorcus are found in this country. 


Family Passalid^e 

The members of this family resemble the stag-beetles in the form of 
the antenna?, but differ in that the mentum is deeply 
emarginate, with the ligula filling the emargination. 

A single, widely distributed species is found in the 
United States; this is the horned passalus, Passalus 
cormltus (Fig. 278). It is a large, shining, black bee- 
tle, with a short horn, bent forwards, on the top of the 
head. This beetle and its larva are found in decaying 
wood. The larva appears to have only four legs, the 
hind legs being shortened and modified so as to form 
part of a stridulating organ. 

The beetles of this genus are common throughout 
the tropics of both hemispheres. According to the 
observations of Ohaus, which have been confirmed by 
Professor Wheeler, these beetles are social. They form 
colonies, consisting of a male and female and their progeny, and make 
large, rough galleries in rather damp, rotten logs. The parent beetles 
triturate the rotten wood and apparently treat it with some digestive 
secretion which makes it a proper food for the larva?, since their mouth- 
parts are too feebly developed to enable them to attack the wood directly. 
All members of the colony are kept together by stridulatory signals. The 
stridulatory organ of the adult consists of patches of minute denticles on 
the dorsal surface of the abdomen, which may be rubbed against similar 
structures on the lower surface of the wings. 


Fig. 278. 


Family Cerambycid^; 

The Long-homed Beetles or Cerambycids 

This is a very large family, there being more than eleven hundred 
described species in North America alone. As a rule the beetles are of 
medium or large size, and graceful in form; many species are beautiful 
in color. The body is oblong, often cylindrical. The antenna? are long, 
often longer than the whole body; but except in one genus, Prionus, they 
are only eleven- jointed, as with most beetles. The legs are also long, and 


CO LEO PT ERA 


161 


the tarsi are apparently four-jointed, the fourth segment being very 
small and hidden; the third segment of the tarsi is strongly 
bilobed (Fig. 279). 

They are strong flyers and swift runners; but many of 
them have the habit of remaining motionless on the limbs 
of trees for long intervals, and when in this apparent trance 
they suffer themselves to be picked up. But, when once 
caught, many species make an indignant squeaking by 
rubbing the prothorax and mesothorax together. 

The larvae are borers, living within the solid parts of 
trees or shrubs, or beneath bark. They are white or yel- 
lowish grubs. The body is soft, and tapers slightly 
from head to tail (Fig. 280); the jaws are power- 
ful, enabling these insects to bore into the hardest 
wood. The larval state usually lasts two or three 
years. The pupa state is passed within the bur- 
row made by the larva ; frequently a chamber is 
made by partitioning off a section of the burrow 
with a plug of chips; but sometimes the larva 
builds a ring of chips around itself just beneath the bark before 
changing to a pupa. The pupal state is comparatively short, 
lasting only a few days or weeks. 


Fig. 


Fig. 2 


THE PRIONIDS 


The larger of the long-horned beetles constitute a subfamily. They 
are distinguished from other cerambycids by having the sides of the 
prothorax prolonged outwards into a thin margin, which is more or less 
toothed. The wing-covers are usually leathery in appearance, and of a 
brownish or black color. The following are our best-known species. 

The broad-necked prionus, Prionus laticollis. — This is the largest of 
our common species; but the individuals 
vary from 1 to 2 inches in. length. It is of 
a pitchy-black color, and of the form shown 
in Figure 281. The antennae are twelve- 
jointed in both sexes. The larva is a large, 
fleshy grub, and infests the roots of grape, ap- 
ple, poplar, and other trees. 

The tile-horned prionus, Prionus imbricornis, 
is very similar to the preceding species but 
can be distinguished at a glance by the form 
of the antennae. In the antennae of the male 
the number of segments varies from eighteen 
to twenty, while in the female the number 
varies from sixteen to seventeen. The popular 
name refers to the fact that the segments 

of the antennae of the male overlap one another like the tiles on a 
roof. The larva infests the roots of grape and pear, and also feeds upon 
the roots of herbaceous plants. A closely related species, Prionus califor- 
nicus, occurs on the Pacific Coast. The larva is from 2§ to 3 inches 
long. 


l62 


THE STUDY OF INSECTS 


Fig. 282. 


THE TYPICAL CERAMBYCIDS 

In this group the prothorax is rounded on the sides, the tibise 
of the fore legs arc not grooved, and the palpi are never acute at the tip. 
There are nearly four hundred American species, representing more than 
one hundred genera. The few species mentioned below are 
those that the beginning student is most likely to meet. 

The ribbed pine-borer, Rhagium lineatum. • — This is a 
gray beetle mottled with black, and has a narrow thorax, 
with a spine on each side (Fig. 282). It received its name 
because of the three ridges extending lengthwise on each 
wing-cover. Its larva bores in the wood of pine-trees. On 
one occasion the writer found many of them in a pine-tree 
eight inches in diameter, which they had bored through and through. 
When the larva is full-grown it makes a hole nearly through the thick 
bark of the tree, so that it may easily push its way out after its trans- 
formations; it then retreats a short distance and makes a little ring of 
chips around itself, between the bark and the wood, and changes to a 
pupa within this rude cocoon. The adult beetle remains in this pupal 
cell through the winter. 

The cloaked knotty-horn, Desmocerus palliatus. — This beautiful 
insect is of a dark blue color, with greenish 
reflections. The basal part 
of the wing-covers is orange- 
yellow, giving the insect the 
appearance of having a yellow 
cape thrown over its shoulders 
(Fig. 283). The segments in 
the middle of the antennae are 
thickened at the outer end, so 
that they look like a series of 

knots. The adult is quite COm- Fig. 283. — Desmocerus pallia- 

mon in June and July on elder, 

in the pith of which the larva bores. 

The beautiful maple-borer, Glycobius specibsus. — 
This is a handsome insect, marked with black and 
yellow, as indicated in Figure 284. It lays its eggs 
in midsummer on the trunks of sugar-maples, in the wood of which 
the larvae bore. If an infested tree be examined in the spring the pres- 
ence of these borers can be detected by the dust that 
falls from the burrows. The larvae can be destroyed at 
this time by the use of a knife and a stiff wire. 

The locust-borer, Cyllene robmice. — To the enthusiastic 
entomologist the goldenrod is a rich mine, yielding to the col- 
lector more treasures than any other flower. It gives up its 
gold-dust pollen to every insect-seeker ; and because of this 
generous attitude to all comers it is truly emblematic of 
the country that has chosen it as its national flower. 

Among the insects that revel in this golden mine in the 
autumn is a black beetle with numerous transverse or wavy yellow bands 
(Fig. 285). This beetle is also found on locust-trees, where it lays its 
eggs. The larvae bore under the bark and into the hard wood. 


Fig. 284. 


Fig. 28s. 


CO LEO PT ERA 


163 


The locust-trees have been completely destroyed in some localities 
by the depredations of these larvae. 

The painted hickory-borer, Cyllene caryce. — This beetle resembles the 
preceding so closely that the same figure will represent either. But the 
hickory-borer not only infests a different kind of tree, but appears in 
the spring instead of the autumn. In this species the second segment of 
the hind tarsus is densely pubescent beneath, while it is glabrous in the 
locust-borer. 


Fig. 286. 


THE LAMIIDS 

As in the preceding group, the prothorax is rounded with these 
beetles; but the lamiids are distinguished by having the fore tibia? 
obliquely grooved on the inner 
side, and the last segment of the 
palpi cylindrical and pointed. 
The following are some of the 
more important species. 

The sawyer, Monochamus 
notatus. — This beautiful brown- 
ish-gray beetle is about 1 ^ inches 
long, with antennae as long as 
the body in the case of the fe- 
male and twice as long in the 
case of the male (Fig. 286). 
The larva bores in the sound 
wood of pine and of fir, making, 
when full-grown, a hole h inch 
in diameter. The pupal state 
is passed within the burrow. It sometimes occurs in such numbers as 
to kill the infested trees. 

The round-headed apple-tree borer, Saperda Candida. — Excepting 
the codling-moth, which infests the fruit, this is the worst enemy of the 
apple that we have. Its common name is used to distinguish it from the 
flat-headed apple-tree borer, already described, the larva of this species 
being nearly cylindrical in form (Fig. 280). The eggs are laid on the 
bark of the trunk of the tree late in June or July. The larva at first 
bores in the soft sap-wood, making a disk-shaped mine; after this it 

works in an upward direction in the harder 
wood, and at the close of its larval existence 
comes to the surface several inches above the 
place it entered. It requires nearly three 
years for this larva to attain its growth; it 
changes to a pupa, near the upper end of its 
burrow, about the middle of May, and emerges 
as a beetle in June. The beetle (Fig. 287) is 
of a pale brown color above, with two broad 
white stripes extending the whole length of the 
body. Although the larva is found chiefly in 
apple, it infests many other trees. The presence of the borers can be de- 
tected by the sawdust-like castings which the larvae throw out at the 
entrances of their burrows. 


Fig. 287. 


i6 4 THE STUDY OF INSECTS 

The two-spotted oberea, Oberea bimaculata, is sometimes a serious 
pest, boring in the canes of blackberry and raspberry. The larva re- 
sembles that of the preceding species. The adult (Fig. 
288) is .about h of an inch in length and of a dee]) black 
color, except the prothorax, which is yellow. There are 
usually two or three black spots on the pronotum, but 
frequently these are wanting. 

The red milkweed-beetles, Tetrabpes. 
- There are several species of bright red 
beetles that are common on milkweeds (Asclepias). 
These belong to the genus Tetraopes. Our most com- 
mon species (Fig. 289) is T. tetraophthalmus . In this 
species there are four black spots on each wing-cover, and the antennae 
are black and not ringed with a lighter color. The larva bores in the 
roots and the lower parts of the stems of milkweeds. 

Family Chrysomelids 

The Leaf-beetles or Chrysomelids 

The leaf-beetles are so called because they feed upon the leaves of 
plants both as larvae and adults. They are usually short-bodied, and 
more or less oval in outline ; the antennas are usually of moderate length ; 
and the front is not prolonged into a beak. The legs are usually short, 
and are furnished with tarsi of the same type as those of the preceding 
family (see Fig. 279, p. 161). 

Although we are unable to cite any characteristic that will invariably 
distinguish these beetles from the preceding family, the student will 
rarely have any difficulty in making the distinction. The beetles of the 
genus Donacia, described below, are the only common ones that are 
liable to be misplaced. In other cases the more or less oval form of the 
body, and the comparatively short antennae, and the leaf-feeding habits, 
will serve to distinguish the chrysomelids. 

The leaf -beetles are nearly all comparatively small, the Colorado 
potato-beetle being one of our larger species. 

The eggs are usually elongated and yellowish, and are laid upon the 
leaves or stems of the plants upon which the larvae feed. Many of the 
larvae live exposed on the leaves of plants; others that live in similar 
situations cover themselves with their excrement; some are leaf -miners; 
and a few, as the striped squash -beetle, bore in the roots or stems of 
plants. 

This is a large family, of which nearly one thousand North American 
species are known. The following illustrations will serve to 
show the variations in form and habits. 

The long-horned leaf-beetles, Donacia. — These are the 
common leaf-beetles that are liable to be mistaken for ceram- 
bycids. They are of elongated form, with slender antennae 
(Fig. 290). They measure from | to f inch in length, and 
metallic color — either greenish, bronze, or purplish. The 
lower side of the body is paler and is clothed with very fine hair which 
serves as a water-proof coat when the insect is submerged. The larvae 
feed upon the roots or in the stems of aquatic plants; and the adults 


COLEOPTERA 


165 


are found on the leaves of the same plants. We have many species, but 
they resemble one another so closely that it is difficult to separate 
them. 

The asparagus-beetle, Crioceris aspdragi. — This 
is a small red, yellow, and black beetle, that gnaws 
holes in the heads of young asparagus, and lays 
oval, black eggs upon them. The larvae, which are 
small, brown, slug-like grubs, also feed upon the 
young heads in the spring, and later in the season a 
second brood feed upon the full-grown plant. Figure 
291 represents a head of asparagus bearing the eggs 
of this beetle, also a beetle and a larva enlarged. 
The beetle measures about \ of an inch in length. 

The grape rootworm, Fidia longipes. — This in- 
sect is the most destructive enemy of the grape 
occurring east of the Rocky Mountains. The adult 
is a small grayish-brown beetle, measuring about \ 
of an inch in length. It feeds on the leaves in July, 
eating out characteristic chain-like holes. The eggs 
are laid beneath the loose bark of the vines. On 
hatching, the larvas drop to the ground and burrow down to the roots, 
which they destroy, causing the death of the vine, Most of the larvae 
do not transform till the following spring. 

The Colorado potato-beetle, Leptinotarsa dectrrnlinedta. — A good 
many insect tramps have come to us from Europe and from the Orient, 
and appropriated whatever pleased them of our growing crops or stored 
grain. But two of our worst insect pests have swarmed out on us in 
hordes from their strongholds in the region of the Rocky 
Mountains. These are the Rocky Mountain locust and the 
Colorado potato-beetle (Fig. 292). The latter insect dwelt 
near the base of the Rocky Mountains, feeding upon the 
sand-burr (Solanum rostratum), until about the year 1859. 
At that time it began to be a pest in the potato-fields of the 
settlers in that region. Having acquired the habit of feeding upon the 
cultivated potato, it began its eastward march across the continent, 
spreading from potato patch to potato patch. At first the migration 
took place at about the rate of fifty miles a year, but later it was more 
rapid; and in 1874 the insect reached the Atlantic Coast. 

The adult beetles hibernate in the ground; they emerge early in April 
or May, and lay their eggs on the young potato plants as soon as they 
appear; both larvae and adult beetles feed on the foliage of the potato. 
The larvae enter the ground to transform. This pest is usually controlled 
by the use of Paris green. 

The diabroticas. Several very important pests belong to the genus 
Diabrotica. They are chiefly greenish-yellow beetles, marked with black 
stripes or spots. The striped diabrotica, D. vittdta, has two black stripes 
on each wing-cover. The adult feeds on the leaves of cucumber, squash, 
and melon; and the larva, which is a slender, worm-like creature, bores 
in the stems and roots of the same plants. The twelve-spotted diabrotica, 
D. duodecim punctata, and Diabrotica soror, agree in having six black spots 
on each wing-cover. The former is very common in the East; the latter 
occurs on the Pacific Coast, and is the most destructive of all of the 


Fig. 292. 


i66 


THE STUDY OF INSECTS 


Fig. 293. 


diabroticas. Diabrotica longicomis is a green species, which feeds on the 
pollen and silk of corn and on the pollen of other plants. Its larva is 
Known as the corn rootworm; it is very destructive to corn in the 
Mississippi Valley. Its injuries are greatest where corn is grown on the 
same land year after year; hence a rotation of crops should be practised 
where this pest is troublesome. 

The jlcabeetles. — There is a group of leaf-beetles, of which we have 
many species, in which the hind legs are fitted for leaping, the thighs 

being very large. These are commonly 
called the fleabeetles. 

The striped fleabeetle, Phyllotreta vit- 
tdta, is exceedingly common on cabbage, 
turnip, radish, mustard, and 
allied plants. It is a small, 
black, shining beetle, with a 
broad, wavy, pale, dull yel- 
low stripe upon each wing- 
cover (Fig. 293) ; it measures 
about -jV of an inch in length. 
These beetles eat numerous 
little pits in the thicker leaves that they 
infest, and minute perforations in the thin- 
ner-leaved plants. The larva is a slender, 
white worm, about | of an inch in length ; 
it feeds on the roots of the plants infested by the 
adult. 

The cucumber fleabeetle, Epitrix ciiciimeris, is a 
common pest of melon and cucumber vines ; it also 
attacks the leaves of potatoes, raspberry, turnip, 
cabbage, and other plants. This is a minute black 
species, measuring less than -^ of an inch in length. 
The body is finely punctured and clothed with a 
whitish pubescence ; there is a deep transverse furrow across 
the hind part of the prothorax; the antennae are dull yellow, 
and the legs are of the same hue, except the posterior femora, 
which are brown. The adult beetles 
feed on the leaves of plants in the 
same manner as the preceding spe- 
cies ; and the larvae on the roots of the t 
infested plants. 

The grape fleabeetle, Haltica 
chalybea. — This is a larger species 
than the two preceding, measuring 
about \ of an inch in length, and is of 
a dark, steel-blue color. It is a great pest in vine- 
yards, eating into the buds of grape in early spring, 
and later gnawing holes in the leaves (Fig. 294). In 
May and June the brown, sluggish larvae may also be found feeding upon the 
surface of the leaves. The full-grown larva is chestnut brown marked with 
black spots (Fig. 295) . It drops to the ground and makes a cell in the earth in 
which it transforms. The most important injury caused by this pest is the de- 
struction of buds in early spring, which causes a great loss of foliage and fruit. 


Fig. 


COLEOPTERA 167 

The wedge-shaped leaf-beetles. — These insects are characterized by the 
peculiar form of the body, which is narrow in front and broad behind. 
In most of the species the body is much roughened by deep pits, and 
usually the pits on the wing-covers are in regular rows. These insects 
and the tortoise-beetles differ from other leaf-beetles in having the fore 
part of the head prominent, so that the mouth is con- 
fined to the under surface. Some of the larvae feed ex- 
ternally upon the leaves and bear a parasol composed 
of their excrement; other species are leaf -miners. 
Baliosus rubra is a good representative of this group (Fig. 
296). It varies in length from £ to £ of an inch. It 
is of a reddish color, with the elevated portions of 
the elytra more or less spotted with black. The FlG - 2 <> 6 - 

larva mines in the leaves of apple, forming a blotch-mine; the transforma- 
tions are undergone within the mine. We have also found this species 
mining the leaves of basswood in great numbers. 

The tortoise-beetles. — Among the more beautiful Coleoptera are cer- 
tain bright golden, green, or iridescent beetles found on the leaves of 
sweet potato, morning-glory, nettle, and other plants. In these beetles 
the body is flattened below and convex above; the head is nearly or 
quite concealed beneath the prothorax; and the margins of the pro tho- 
rax and elytra are broadly expanded, forming an approx- 
imately circular or oval outline, and suggesting a 
resemblance to the shell of a tortoise (Fig. 297). Not all 
of the species are iridescent ; and in the case of those that 
are, the brightness of the colors is said to depend on the 
emotions of the insect. What a beautiful way to express 
one's feelings — to be able to glow like melted gold when 
one is happy! Unfortunately for the beauty of our collections, these bright 
colors disappear after the death of the insect. 

The larva? of the tortoise-beetles are flattened, and have the margin 
of the body fringed with spines. At the caudal end of the body there is a 
forked appendage which serves a very strange purpose. This fork is 
bent forward over the backhand to it are attached the cast-off skins of 
the larva and its excrement; these constitute a parasol. When about to 
change to the pupa state these larva? fasten the caudal end of the body 
to the underside of a leaf; the skin then splits open, and is forced back 
to this end of the body, where it remains. 

The black-legged tortoise-beetle, Cassida nigripes, is a beautiful 
golden species which lives on the vines of the sweet potato. It is a little 
over j of an inch in length and each wing-cover bears three black spots 
arranged in a triangle. The beetle loses its brilliant tone if disturbed 
and when it dies the golden color fades to a yellowish-brown. 


Family Mylabrid^e 

The Pea-weevil Family 

These are small beetles, the larva? of which live in the seeds of legu- 
minous plants. The head of the adult is prolonged into a broad beak; 
and the wing-covers are rather short, so that the tip of the abdomen is 


i68 


THE STUDY OF INSECTS 


always exposed (Fig. 298). This is a comparatively small family; ninety- 
three species are listed in our fauna, of which eighty-one belong to the 
genus Mylabris. 

The pea-weevil, Mylabris pisorum. — "Buggy peas " are 
well known in most sections of our country; but just how 
1 the " bugs " find their way into the peas is not so generally 
understood. The eggs of the pea-weevil are laid upon the 
pod while the peas are quite small; when the larvae hatch 
they bore through the pod into the young peas. Here they 
feed upon the substance of the seed, which ripens, however, and in some 
cases will germinate when planted. The larva before transforming eats a 
circular hole on one side of the seed, leaving only a thin scale, which is 
easily pushed away by the mature beetle. The adult is about \ of an 
inch in length; it is dark brown, with a few white spots on the wing- 
covers, and one on the prothorax near the middle. Sometimes the beetles 
leave the peas during the autumn or winter; but as a rule they remain 
in the seed till spring, and are often planted with it. Seed peas should 
be placed in water, and the infested ones, which will float, should be 
picked out and destroyed. This species is not known to oviposit on dry 
peas. 

The bean-weevil, Mylabris obtectus. — This species resembles the 
preceding quite closely; but it is a little smaller (Fig. 298), and lacks 
the white markings characteristic of M. pisorum. It infests beans, and 
often several individuals inhabit a single bean. The eggs are laid within 
the pod, being pushed through a slit which the female gnaws through 
the pod. This species will oviposit on dry beans, peas, and other grain, 
and will continue to breed for many generations in stored beans and 
peas. 


The Snout-Beetles 
The Group Rhynchophora * 

The five families included in this series constitute a well-marked 
division of the order, which has long been known as 
the Rhynchophora or snout-beetles. These names were 
suggested by the fact that in many of these insects the 
head is prolonged so as to form a snout or beak; but 
it should be remembered that, while these names are 
very appropriate for a large part of this series, in some 
members of it the head is not thus prolonged. This is 
especially true of the last two families, the bark-beetles 
and timber-beetles, in which the beak is either want- 
ing or extremely short and broad. 

The most distinctive features characterizing this se- 
ries of families are the following: the suppression of the 
gula, the gular sutures being confluent (Fig. 299, gs); 
the absence of sutures between the presternum and the 
episterna and epimera; the meeting of the epimera of 
the prothorax on the middle line behind the prosternum 
(Fig. 299, em); and the palpi being usually short and rigid. 


Fig. 299. 


* Rhynchophora: rhynchos (New Latin), snout; phoros (<t>bpos), bearing. 


COLEOPTERA 169 

Family Brentid^ 
The Primitive Weevils 

This family is confined chiefly to tropical regions; only six species 
are found in the United States, and but one of these in the North. 

The northern brentid, Eupsalis minuta. — In the female 
the head is prolonged into a slender snout ; but in the male 
the snout is broad and flat, and is armed with a pair of 
powerful jaws (Fig. 300). These are weapons of offence, 
for the males fight desperately for their mates; and too, the 
males are generally larger than the females. In these re- 
spects these insects resemble the stag-beetles, the males of Fig 5oo 
which also fight for their mates. 

The northern brentid is found beneath the bark of recently felled or 
dying oak, poplar, and beech trees in the solid wood of which the larvas 
bore; and is widely distributed over the United States and Canada. 

Family Platystomid.43 
The Fungus Weevils 

This family includes a small number of snout- beetles in which the 
beak is short and broad, and the labrum is present; the antennae are not 
elbowed, and the terminal segments rarely form a compact club; the 
palpi are flexible; and the prothorax bears a transverse elevated ridge at 
or near its base. 

The larva? of many species infest woody fungi, others breed in the 
smut of corn and wheat, and still others bore in dead wood. The larvae 
of one cosmopolitan species, known as the coffee-bean weevil, Arceocerm 
fascictddtus, attack seeds of various plants. 

Sixty-two species of this family are known to occur in America north 
of Mexico. This family is the Anthribidae of many authors. 

Family Curculionid^e 
The Curculios or Typical Snout-beetles 

The Curculionidae is a very large family; it is represented in America 
north of Mexico by more than eighteen hundred species; to it belong 
four-fifths of all our Rhynchophora. This family includes the typical 
snout-beetles, the head being prolonged into a well-defined beak, which 
is usually long and curved downward. 

The following are some of the more important members of this family. 

The sweet potato weevil, Cylas formicdrius , is an Asiatic species which 
has invaded the Gulf states. The beetle is somewhat ant-like in form, 
a fact which suggested its specific name. It is about f of an inch in 
length. The elytra, head, and snout are bluish-black while the prothorax 
is reddish -brown. Both larvas and adults bore into the stems and tubers 
of the sweet potato and sometimes do very serious damage. 

The imbricated snout-beetle, Epiazrus imbriedtus, is usually a dull, 
silvery white beetle with brown markings; but the species is quite vari- 


i;o THE STUDY OF INSECTS 

able in color. It is represented, somewhat enlarged, in Figure 301. It 
is omnivorous, gnawing holes in various garden vegetables, strawberry- 
plants, and other fruits. The greater part of the insect is 
clothed with imbricated scales, which suggested the spe- 
cific name. 

The New York weevil, Ithycerns noveboracensis. — This 
is a large species, measuring from f to | of an inch in 
length. It is black, rather sparsely clothed with a mix- 
ture of ash-gray and pale brown prostrate hairs which 
give it a black-spotted appearance. The beak is short and 
broad. The mandibles are prominent, not very stout, 
IG ' 301 ' and emarginate at the tip, with an inferior cusp. The 

antennae are not elbowed; the first segment is longer than the second; 
and the terminal segments form a small, oval club. 

This species breeds in the twigs and tender branches of oak, hickory, 
and possibly other forest trees. The adult beetles appear in early spring, 
and sometimes do much damage to fruit-trees by eating into buds, and 
gnawing the tender bark on new growth. They can be caught by jarring 
them on to sheets or by the use of a plum-curculio catcher. (This 
weevil is placed in a separate family, Belidcz, by some authors.) 

The strawberry crown-girdler, Brachyrhmus ovdtus. — This is a dark 
brown, almost black, snout-beetle, about £ of an inch in length, which 
often invades dwellings in search of shelter, in the Northern States and 
Canada. The larvae feed on the roots of the strawberry, cutting them 
off near the crown. The adults feed on the foliage. In the adult, the 
hind wings are wanting and the elytra are grown together. 

The black vine-weevil, Brachyrhinus sulcatus. — This beetle is larger 
than the preceding species, measuring % of an inch in length; it is black, 
with small patches of yellowish hairs on the elytra. The larvae destroy 
the roots of strawberries; and both larvae and adults infest various green- 
house plants. 

The plum-curculio, Conotrachelus nenuphar. — This is the insect that 
stings plums, often destroying a large portion of the fruit; the larva is 
also the well-known " worm " of " wormy " cherries. This species is the 
most destructive insect that infests plums, cherries, and other stone 
fruits; it also breeds in apple. Its presence in an orchard can be deter- 
mined early in the season by a peculiar mark it makes when laying its 
eggs in the young fruit. The female beetle makes an incision, with her 
snout, through the skin of the fruit. In this incision she lays a single 
egg, which she pushes with her snout to the bottom of the cavity that 
she has prepared. She then makes a crescent-shaped incision in front of 
the one containing the egg. This last cut undermines the egg. leaving it 
in a little flap. The larvae feed within the fruit. In the case of the plums 
the infested fruit falls to the ground; but not so with cherries. When 
full-grown the larvae go into the ground to transform. This species in- 
fests nectarines, apricots, and peaches, as well as plums and cherries. 

The strawberry -weevil, Anthonomus signdtus, infests strawberry, 
blackberry, raspberry, and dewberry. The female beetle, after laying an 
egg in the flower-bud, causes it to fall by cutting the pedicel; the larva 
develops within the fallen bud. 

The cotton-boll weevil, Anthonomus grdndis, is one of the most serious 
insect pests known in the United States. It infests only cotton. The 


COLEOPTERA 


171 


Fig. 302. — The Mexican cotton- 
boll weevil, much enlarged. 


Fig. 303. 


egg is deposited in a young boll, which the larva destroys. The adults 
(Fig. 302) also feed upon the young bolls and upon the leaves. This 
species is a native of Central America. It spread through Mexico, and 
entered Texas about 1890. Since that time it 
has spread over a large part of the cotton belt. 
Very extensive investigations of this pest have 
been made by the Federal Government and by 
several state governments ; and much literature 
regarding it is available to those interested. 

The acorn-weevil, Balaninus 

rectus, has a slender snout twice 

as long as the body (Fig. 303). 

The female drills a hole in the 

young acorn with this snout and then lays an egg in the 

opening afterwards pushing it to the bottom of the hole 

with her snout. The grub devours the interior of the 

acorn. 

The hickory-nut weevil, Balaninus nasicus, breeds 

in hickory nuts and the chestnut weevil, Balaninus 
probosctdeus, causes wormy chestnuts. Each of these weevils have a long 
slender snout, longer than the body. 

Among the smaller members of this family are two exceedingly im- 
portant pests of stored grains; these are the granary- weevil, Calandra 
granaria, and the rice-weevil, Calandra oryzce. The rice-weevil is so 
called because it was first found in rice in India; but it infests various 
kinds of stored grain ; and in the South it is fully as important a granary- 
pest as is the granary-weevil. 

The two species are quite similar in appearance; but the granary- 
weevil is the larger, measuring from f to } of an inch in length ; while the 
rice-weevil measures less than \ of an inch in length, and differs from the 
granary-weevil in having the elytra marked with four reddish spots. 
The thorax of the rice-weevil is closely pitted with round punctures; 
that of the granary- weevil, with sparse elongate punctures. 
The adult female of both of these species gnaws a tiny 
hole in a kernel of grain and then deposits an egg in it. 
The larva feeds on the grain, becomes full-grown, and 
transforms within the kernel. The adult continues the in- 
jury begun by the larva, eating out the inside of the kernel. 


Family Platypodid^e 

This is a small family, which is represented in our fauna 
by a single genus, Platypus, of which only five species have 
been found in America north of Mexico; these are found 
chiefly in the South and the far West. 

Formerly this group was classed as a subfamily of the 
Scolytidae. It is distinguished from the Scolytidae by the 
fact that the first segment of the anterior tarsi is longer 
than the second, third, and fourth together. The form 
of the body is cylindrical (Fig. 304); and the head is 
large, wider than the prothorax. 


Fig. 304. — Platy- 
pus wilsoni, female. 
(After Swaine.) 


172 


THE STUDY OF INSECTS 


The species of this genus attack many kinds of conifers and deciduous 
trees. They bore deeply into the heart-wood, making " pin-holes " that 
often render lumber useless. The eggs are deposited in the galleries; 
and the larvae feed on a fungus, which is cultivated by the beetles and is 
known as ambrosia. In this respect Platypus resembles several genera of 
the Scolytidae, which also bore in solid wood and feed on ambrosia; all 
of these are known as ambrosia-beetles. The galleries of ambrosia-beetles 
are usually blackened by the fungus. See further account of the ambro- 
sia-beetles in the discussion of the next family. 


Famil y Scolytidae 

The Engraver-beetles and the Ambrosia-beetles 

The members of the family Scolytidae are mostly of cylindrical form 
(Fig. 307) and of small or moderate size; some species measure only 
■^s of an inch in length, but others are much larger, attaining a length of 
I of an inch or more. They are usually brown, 
sometimes black, and with many the hind end 
of the body is very blunt, as if cut off. The an- 
tennae are elbowed or bent in the middle, and are 
clubbed at the tip; the tibiae are usually serrate; 
and the first segment of the -anterior tarsi is shorter 
than the second, third, and fourth together. 

A few members of this family infest herbaceous 
plants; our most important one of these is the 
following. 

The clover-root borer, Hylastinus obscurus. — 
This pest was introduced from Europe and has 
become the most serious enemy of clover, especially 
red clover and mammoth clover, in New York 
State and in other sections of the North. It bores 
in the roots of plants beginning their second year 
of growth and destroys them (Fig. 305). Where 
it is common it is practically impossible to keep 
fields in clover longer than the second summer 
after seeding. In these regions it is the common 
practice to seed with clover and timothy mixed; 
after the clover disappears the field becomes a 
timothy meadow. No practical method of control 
of this pest has been found. 

Most scolytid beetles infest woody plants; 
among them are some of the most destructive 
enemies of forest-trees, and a few attack fruit- 
trees. As a rule they are more liable to attack- 
sickly trees, but their injuries are not confined to 
these. 

The scolytid beetles exhibit two radically 

different types of habits; and from this point of 

view they can be grouped into two groups: first 

the engraver-beetles or bark-beetles; and second, 

7jE k wK«T the ambrosia-beetles or timber-beetles. These two 


\ 


COLEOPTERA 


i73 


Fig. 306. 


groups, however, do not represent a natural division of the family based on 
structural characters. The peculiar habits of the ambrosia-beetles are be- 
lieved to have arisen independently in different parts of the series of 
scolytid beetles. 

The Engraver-beetles or Bark-beetles 

If the bark be pulled from dead branches or trunks of trees, the inner 
layer and the sap-wood will be found, in many cases, to be ornamented 
with burrows of more or less regular form. The smoothly cut figures 
are the mines of en- 
graver-beetles, which 
are also known as 
bark-beetles. Many 
kinds of these en- 
gravings can be 
found, each char- 
acteristic of a partic- 
ular species of 
engraver-beetles. A 
common pattern is 
shown in Figure 306. 

The different species of engraver-beetles vary so greatly in the details 
of their habits that it is difficult to make generalizations regarding them 
in the space available here. In a common type, the adult beetle, after 
penetrating the bark, makes a tunnel in the inner layer of the bark or in 
the sap-wood or in both; this is known as the egg-tunnel, and may be 
either simple or branched. In the sides of the tunnel, most species make 
niches, the egg-niches, in which the eggs are laid. The larva when 
hatched feeds on the bark or sap-wood or both and thus makes a lateral 
tunnel. These lateral tunnels made by the larvae often extend parallel 
in a more or less regular manner. 

While most of the engraver-beetles infest forest-trees, the two follow- 
ing species are well-known pests of fruit-trees. 

The fruit-tree bark-beetle, Eccoptogaster rugulosus. 
— This species infests apple, quince, plum, peach, and 
other stone-fruits. It is sometimes called the shot- 
hole borer by fruit-growers on account of the small en- 
trance holes of its burrows. The adult beetle measures 
from x 1 ^ to yV of an inch in length, and is dark brown or 
nearly black. It infests chiefly sickly trees. 

The peach-tree bark-beetle, Phthorophlams limi- 
naris. — This species resembles the preceding in size 
and habits, except that its injuries are confined 
chiefly to peach and cherry. It can be distinguished 
from the fruit-tree bark-beetle by the fact that the club 
of the antennas is lamellate, an unusual feature in this family (Fig. 307). 

The Ambrosia-beetles or Timber-beetles 

Certain members of the family Scolytidas differ in habits from the 
engraver-beetles or bark-beetles in a remarkable manner; these are those 
known as ambrosia-beetles or timber-beetles. They are termed ambrosia- 


Fig. 307. - 
la-us liminaris. 


Phlhoroph- 


174 


THE STUDY OF INSECTS 


beetles because they cultivate fungi, commonly called ambrosia, upon 
which they feed; and timber-beetles, because they burrow in the solid wood. 

The galleries of the ambrosia-beetles can be distinguished from those 
of other wood-boring insects by the fact that in all of their ramifications 
they are of uniform size and free from wood-dust and other refuse, and their 
walls are stained black i >r 1 >r< >wn by the fungus that is grown upon them. 

The galleries of different species differ in form; but usually there is a 
main gallery, which extends deeply into the solid wood and is often 
branched; and extending from the sides of the main gallery there are 
short chambers, termed cradles, in each of which an egg is laid and a 
larva reared (Fig. 308) . In some species, the female deposits her eggs loosely 
in the galleries, and the young and old live together in the same quarters. 


Fig. 308. — Gallery of Monarthrum mail in maple. (From Hubbard.) 

The galleries are excavated by the adult beetles. In some species 
the gallery is started by a single female, in others the males assist the 
females in this work. The entrances through the bark to the galleries 
are similar to those made by the bark-beetles and like them are known 
as " shot-holes." Under favorable conditions colonies may continue their 
excavations during two or three generations. 

The fungi upon which these beetles feed are carefully cultivated by 
them. So far as is known, each species of ambrosia-beetle cultivates 
only a single species of fungus, and only the most closely allied species 
have the same food-fungus. The fungus is started by the mother-beetle 
upon a carefully packed bed or layer of chips. It is probable that some 
conidia are brought for this purpose from the gallery in which the female 
was developed. The excrement of the larvae is used in some and prob- 
ably in all the species to form new beds for the propagation of the fungus. 

In those species in which the larvae are reared in separate cradles, 
" the mother-beetle is constantly in attendance upon her young during 
the period of their development, and guards them with jealous care. 
The mouth of each cradle is closed with a plug of the food-fungus, and 
as fast as this is consumed it is renewed with fresh material. The larvae 
from time to time perforate this plug and clean out their cells, pushing 
out the pellets of excrement through the opening. This debris is promptly 
removed by the mother and the opening again sealed with ambrosia. 
The young transform to perfect beetles before leaving their cradles." 


COLEOPTERA 


i75 


While the ambrosia-beetles are chiefly injurious to forest-trees, there 
are certain species that injure wine and beer casks; and one species, 
the pear-blight beetle, Anisandrus pyri, sometimes infests the tips of 
pear and apple branches, causing an injury that is often mistaken for the 
bacterial disease known as pear-blight. 

Nearly four hundred species of scolytid beetles, representing many 
genera, have been described from America north of Mexico. 

FAMILIES OF COLEOPTERA NOT DISCUSSED 

The order Coleoptera includes a great number of families the mem- 
bers of which are rare or little known. The special student of the beetles 
is referred to " An Introduction to Entomology " by J. H. Comstock and to 
special treatises on the Coleoptera for an account of the families which we 
have not been able to discuss in this Manual. 


Omophronidae 

Haliplidee 

Amphizoidas 

Rhysodidas 

Clavigeridas 

Pselaphidae 

Histeridas 

Sphasritidae 

Scaphidiidas 

Platypsyllidag 

Leptinidae 

Scydmaenidae 

Clambidas 

Brathinidas 

Corylophidas 

Trichopterygidae 

Sphasriidae 

Psephenidas 

Dryopidae 

Elmidae 

Ptinidae 

Anobiidas 

Bostrichidas 

Lyctidae 

Nosodendridas 

Byrrhidae 


Chelonariidas 

Cupesidae 

Dascillidas 

Eucinetidae 

Helodidas 

Nitidulidae 

Rhizophagidae 

Ostomidas 

Eucnemidae 

Cerophytidas 

Throscidae 

Phalacridas 

Mycetophagidae 

Cryptophagidas 

Erotylidas 

Rhipiceridae 

Derodontidas 

Cleridas 

Corynetidae 

Melyridas 

Lymexylidae 

Cebrionidae 

Plastoceridas 

Phengodidas 

Lycidae 

Micromalthidas 


Endomychidae 

Lathridiidae 

Monotomidas 

Heteroceridae 

Colydiidae 

Murmidiidae 

Mycetaeidas 

Cisidae 

Georyssidag 

Lagriidas 

Othniidas 

Sphindidas 

Eurystethidae 

Alleculidas 

Monommidae 

Melandryidae 

Pythidae 

CEdemeridae 

Cephaloidae 

Pedilidas 

Anthicidas 

Euglenidae 

Pyrochroidas 

Rhipiphoridas 

Mordellidas 


CHAPTER XXI 
ORDER STREPSIPTERA * 


The Stylopids or Twisted-winged Insects 

The members of this order are small, endoparasitic insects, which prey 
on other insects. Only the males are winged; in this sex, the fore wings are 
reduced to club-shaped appendages; the hind wings are large compared with 
the size of the tiny body, fan-shaped, furnished with radiating wing-veins, 
and folded longitudinally when at rest. The adult female is larviform and 
legless. The mouth-parts are vestigial or wanting; the alimentation is 
probably by osmosis. Both sexes undergo a hypermetamorphos is . 

The order Strepsiptera comprises insects that were formerly classed 
as a family of the Coleoptera, the Stylopidae; for this reason, these in- 
sects have been known as the stylopids. Recently since the establish- 
ment of the order Strepsiptera, the name the twisted-winged insects, 
derived from the technical name of the order, has been proposed for them ; 
but the old name is less cumbersome, and will probably continue to be 
used. 

The stylopids are small insects which live par- 
asitically within the bodies of other insects, chiefly 
bees, wasps, digger wasps, and certain Homoptera. Their 
small size and the fact that nearly their entire ex- 
istence is passed within the bodies of their hosts re- 
sult in their being rarely seen except by those who 
are searching for them. During the first stadium the 
young larvae of both sexes are free, and the adult 
winged male leads a free existence for a brief period. 

The stylopids are most easily found by examining 
adult individuals of the species of insects that they in- 
fest, in which may be found adult females and male 
men of 'styiopjzed pupa? of the parasites. The presence of a stylopid is 
indicated by the projecting of the head end of the body 
from between two of the abdominal segments of the host (Fig. 309). 
Frequently a single host will contain several parasites. 

Figure 310 will serve to illustrate the appearance of an adult male 
stylopid. The more striking features are the flabellate antennas; the 
large, stalked, compound eyes; the shortness of the prothorax and the 
mesothorax, and the great length of the metathorax; the reduction of 
the fore wings to club-shaped appendages; and the large size of the 
hind wings. 

The antennas of adult males differ greatly in form in the different 
families of this order. The number of antennal segments varies from four 
to seven. 

* Strepsiptera: strepsis (arpkipis), a turning; pteron (irTepov), a wing. 

176 


Fig. 3og. — Abdo- 


STREPSIPTERA 177 

The mouth-parts of the males are greatly reduced and the mouth 
opening is small. The labrum and labium are wanting as distinct parts. 


Fig. 310. — A male stylopid. (After Pierce.) 

In some species the mandibles are slender, curved and scimitar-like while 
the maxillae are two-segmented. In others the mandibles are greatly 
reduced. 

The three pairs of legs are similar in form and the abdomen is com- 
posed of ten segments. 

The adult female is very degenerate in form. That part of the body 
which projects from the body of the host is the cephalothorax, the head 
and thorax being consolidated into a single disk-like region. The abdo- 
men, which is within the body of the host, is a great sac filled with eggs. 
The body of the adult female is inclosed in the skin of the last larval 
instar, which is termed the puparium; but there is no pupal stage in 
this sex. 

Owing to their parasitic life the development and life-cycles of these 
insects are very complex and remarkable. The young larva is very active 
for it must hunt around and find a host insect. Many of these larva;, of 
course, never find a host and therefore starve. This contingency is 
provided for, however, because a female stylopid has been known to 
produce as many as 2000 young. After the young stylopid finds a host 
it bores to the inside of the body and begins its parasitic life. The 
larvae pass through several molts and assume different forms in their 
progress toward maturity, the females after the early stages differing in 
their development from the males. The female remains larval-like in 
form even when full-grown. 

The order, Strepsiptera, is well represented in this country, ninety- 
seven species having been listed and probably there are many undis- 
covered species. 


CHAPTER XXII 


ORDER MECOPTERA* 


Head 


Fig. 311 
and tail of Panorpa 


The Scorpion-flies and Their Allies 

The winged members of this order have four wings; these are usually 
long, narrow, membranous, and furnished with a considerable number of 
cross-veins; the wings are wanting or vestigial in two genera. The head is 
prolonged into a deflexed beak, at the end of which chewing mouth-parts are 
situated. The metamorphosis is complete. 

This is a small order composed of very remarkable in- 
sects. The most striking character common to all is the 
shape of the head, which is prolonged into a deflexed 
beak (Fig. 311). The beak is formed from the greatly 
elongated clypeus, submentum, and stipes of the maxillae 
» with the rather small, slender mandibles situated at the 

t» K ti P- 

^^i The antennas are long, very slender, and many- 

segmented. The compound eyes are moderately large 
and the legs are long and slender with five-segmented 
tarsi. 

The wings are membranous and are usually long and narrow but in 
certain rare forms they are comparatively broad. The venation of the 
wings is generalized but with many cross-veins. 

The metamorphosis is complete. The larvae are caterpillar-like, with 
three pairs of thoracic legs and with or without abdominal prolegs. The 
pupae are exarate, that is, the wings and legs are free, as in the Coleop- 
tera and Hymenoptera. 

The scorpion-flies. — The most com- 
mon members of this order belong to the 
genus Panorpa, of which there are nearly 
twenty described North American species. 
Figure 312 represents a female of this 
genus. In our more common species the 
wings are yellowish, spotted with black, 
genus are remarkable for the peculiar Panorpa, female 
form of the caudal part of the abdomen (Fig. 313). This 
at first sight reminds one of the corresponding part of a scorpion, and 
suggested the common name scorpion-flies for these insects. But in re- 
ality the two are very different; the last segment of the male Panorpa, 
instead of ending in a sting, like that of a scorpion, is greatly enlarged 
and bears a pair of clasping organs. The tarsal claws are toothed. 

The adults are found resting on the surface of foliage of rank herbage 
growing on the banks of shaded streams and in damp woods where there 
* Mecoptera: mecos (/jljjkos), length; pteron (irrepov), a wing. 

178 


Fig. 313. — Abdomen of 
Panorpa ru/escens. 

The males of this 


MECOPTERA 179 

is a luxuriant undergrowth of herbaceous plants. They feed on dead or 
injured insects and upon fruits; it appears that they rarely if ever cap- 
ture living prey. 

The females lay their eggs in crevices in the earth. The larvae are 
caterpillar-like in form; they have three pairs of true legs and eight 
pairs of abdominal prolegs ; and the body is armed with prominent spines 


Fig. 314. — Larva of Panorpa rufescens, first instar. (After Felt.) 

(Fig. 314); the larvae are carnivorous. The transformation takes place 
in a cell in the ground. 

Boreus. — This genus includes small Mecoptera, our species measuring 
from jV to I of an inch in length, which are often found on snow in 
winter. The wings of the female are vestigial or wanting; those of the 
male, imperfectly developed. The ocelli are wanting. The female has a 
long, protruding ovipositor, which in some species is nearly as long as the 
abdomen. The larva differs from that of Panorpa in lacking the abdom- 
inal prolegs. The pupa state is passed in an earthen cell in the ground. 
Four American species have been described, two from the East and two 
from the West. 

BUtacus. — Insects belonging to this genus have long, narrow wings, 
long legs, and a slender abdomen. They resemble crane-flies very closely 
when on the wing, but can be distinguished by the 
presence of two pairs of wings. They are almost as 
common as Panorpa; and, like the scorpion-flies, are 
found among rank herbage growing on the banks of 
shaded streams and in damp woods where there is a 
luxuriant undergrowth of herbaceous plants. When at 
rest they hang suspended, by their front legs, from 
some support (Fig. 315). The members of this genus 
capture and eat living insects. They are enabled to 
capture their prey by means of their curiously modi- 
fied tarsi, the last two segments of which are armed 
with teeth, and the last segment can be folded back 
against the next to the last segment. In this way there 
fig. 31s. — Natural is formed an efficient grasping organ. It is an interest- 
(From Felt? Bittacus - ing fact that, while in other predacious insects the fore 
legs are the chief organs of prehension, in Bittacus 
the hind legs are used for this purpose fully as often as the others, espe- 
cially when the Bittacus is hanging suspended by its fore legs and cap- 
tures an insect that comes within reach of it. 

Nine North American species of Bittacus have been described. 


CHAPTER XXIII 
ORDER TRICHOPTERA* 


Fig. 316. — Caddice-fly. 


The Caddice-flies 

The members of this order have four wings; these are membranous and 
usually more or less densely clothed with long, silky hairs. In the more 
generalized members of the order, the venation of the wings corresponds 
closely to that of the hypothetical primitive type with but few or no accessory 
veins; in some of the more specialized members of the order, the venation of 
the wings is reduced. The mouth-parts of adults, except the palpi, are 
vestigial. The metamorphosis is complete. 

The caddice-flies are moth-like insects, which 
are common in the vicinity of streams, ponds, 
and lakes, and are frequently attracted to lights at 
night (Fig. 316). The larva? of these insects are the 
well-known caddice-worms ; these live in the water, 
and most of them build cases about their bodies. 
In the adult insect, the body-wall is soft, and is thickly clothed with 
hairs. The two pairs of wings are membranous and usually more or 
less clothed with long, silky hair. In a few forms the wings are naked. 
The hind wings are shorter than the fore wings; but they are usually 
broader. In one species the female is apterous, and in another the wings 
of the female are vestigial. When not in use the wings are folded roof- 
like over the abdomen. 

The eggs of caddice-flies are round or slightly oval in form, 
are laid either in water or upon objects above 
water from which the larvae when hatched can 
find their way into the water. Some species that 
lay their eggs in water descend below the sur- 
face in order to glue their eggs to some sub- 
merged support. So far as is known, most 
caddice-flies, lay their eggs in a mass enveloped 
either in a cement, by which the mass is glued 
to some support, or in a gelatinous covering. In 
the latter case, the covering absorbs water and 
thus increases greatly in size. The form of the gelatinous mass and the 
arrangement of the eggs within it are often characteristic of the species 

(Fig. 317). 

The larvae of caddice-flies, the caddice-worms, found in this country 
are aquatic and most of them build portable cases in which they live and 
which they drag about wherever they go projecting only the front end 
of the body and the legs from the case when they travel. The cases of 
different species differ greatly in form and in materials vised in their con- 
* Triehoptcra: trichos (Opi£, rplxos), the hair; ptcron (ttt(poi>), a wing. 

180 


They 


Fin. 317. — Two egg-masse? 
of caddice-flies: a, Phryganea in- 
terrupta- b, Trianodes sp. (From 
Lloyd.) 


TRICHOPTERA 181 

struction ; but silk is used in building all of them. This silk, like that of 
caterpillars, is secreted by modified salivary glands and is emitted 
through an opening in the labium. 

Some caddice-worms build their cases entirely of silk; but most of 
the case-building species use other materials also; these may be grains 
of sand, small stones, bits of wood, moss, or pieces of leaves; and some 
species fasten shells of small mollusks to their cases. The materials used 
are glued together with silk; and the case is lined with silk, so as to 
form a suitable protection for the soft abdomen. 

When the caddice-worms are full-grown they do not leave the water 
to transform, the pupae being as truly aquatic as the larvae. Some of the 
case-building species change the form and material of their cases at this 
time; and nearly all of them partly close their cases so as to keep out 
intruders and sift; but usually provision is made for the ingress of water 
for respiration. Some species merely cement a stone or grains of sand 
over each opening of the case; others build a silken lid with a slit in it; 
and still others build a silken grating in each end of the case. Within 
these modified cases the larvae transform to pupae. 

In the case of those caddice-flies that emerge from rapidly flowing 
water, as the net-building species, the wings expand instantly when the 
insect reaches the surface of the water and are then fitted for flight; it is 
evident that if much time were required for the wings to become fit for 
use, as is the case with most other insects, the wave succeeding that 
which swept the insect from the water would sweep it back again and 
destroy it. 

The Trichoptera can be regarded as beneficial insects, as the larvae 
form an important element in the food of fishes, and especially of the 
brook trout. Sometimes in cities near rivers, the adults are annoying on 
account of the great numbers of them that are attracted to lights. 

This is a large order and includes several families. Each species of 
those which make cases builds a par- 
ticular kind of tube. Some caddice- 
worms are carpenters, 
building their houses of _ _ „ , , ,. 

o - Fig. 318. — Case of caddice- worm. 

straws or sticks placed 

lengthwise of the body (Fig. 318); but certain species that 
make their houses chiefly of straws fasten the straws cross- 
wise like the logs of a log-house (Fig. 319). These log-house 
fig. 319— Log- builders often have the curious habit of decorating their 
. a m type o case. k ouses j-^ f as tening snail-shells to the outside. 

There are caddice-worm houses closely resembling in plan those just 
described but differing in appearance, being-made of bits of moss. Some- 
times the houses are built of leaves ; these may be fastened so as to form 
a flat case; or are arranged in three planes, so as to form a tube, a cross- 
section of which is a triangle. 

Other caddice-worms are masons, building their houses of grains of 
sand or of small stones. Sometimes these houses are tubes very regular 
in outline, being composed only of grains of sand fastened together with 
silk; but certain species of mason caddice-worms fasten larger stones on 
each side of this tube of sand (Fig. 320). Some of the species that build 
tubes of sand make spiral houses which very closely resemble in form 
snail-shells (Fig. 321). 


l82 


THE STUDY OF INSECTS 


Perhaps the most remarkable species are the net-spinning caddice- 
worms. The best-known of these are species of the genus Hydropsyche, 
the nets of which have been described by many writers. 


Fig. 32a. — Case of Gtrra 
calcarala. (After Lloyd.) 


Fig. 321. — Case 
of H elico psyche. 
(From Lloyd.) 


Fig. 322. — Net of Hydropsyche. 


The larvae of Hydropsyche live only in rapid streams and on the wave- 
beaten shores of lakes. They do not build portable cases, but live in 
tubes composed of silk and debris, and fastened permanently in place; 
sometimes they establish themselves in old worm-holes in submerged 
wood. The most striking feature in their habits, however, is the fact 
that each one builds a net for the capture of its food. This net is built 
adjacent to the tube in which the larva lives; it is funnel-shaped and has 
at its down-stream end an opening in which is built a strainer. This is a 
beautiful object, consisting of two sets of regularly spaced strands of 
silk extending across the opening at right angles to each other (Fig. 322). 
These nets are often built in crevices between stones; but fully as often 
they are built up from a flat surface, as on the brink of a waterfall. 
Much of the coating of dirt with which rocks in such places are clothed in 
summer is due to its being caught in these nets. Algae, larvae, and other 
small animals in the water that passes through the net are held by the 
strainer and thus made available to the caddice-worm for food. 


CHAPTER XXIV 
ORDER LEPIDOPTERA* 


The Moths, the Skippers, and the Butterflies ' 

The winged members of this order have four wings; these are mem- 
branous, and covered with overlapping scales. The mouth-parts are 
formed for sucking. The metamorphosis is complete. 

The members of this order, the moths, the skippers, and the butter- 
flies, are well known to every observer of nature. Their most easily 
observed distinguishing characteristic is that which suggested the name 
of the order, the scaly covering of the wings and body. Every lad that 
lives in the country knows that the wings of moths and butterflies are 
covered with dust, which comes off upon one's fingers when these insects 
are handled. This dust when examined with a microscope is found to be 
composed of very minute scales of regular form. The body, the legs, 
and other appendages are also covered with scales. 

The scales of Lepidoptera are modified setas. That is, they are setae 
which, instead of growing long and slender as setae usually do, remain 
short, but grow very wide as compared with their length. Every grada- 
tion in form can be found from the ordinary hair-like form, which occurs 
most abundantly upon the body, to the short and broad scale, which is 
best seen upon the wings. 

There is a great difference among the 
insects of this order regarding the regular- 
ity of the arrangement of the scales upon 
the wings. With some of the lower moths 
the scales are scattered irregularly over the 
wings. But if the wing of one of the higher 
butterflies be examined with a microscope, 
the scales will be found arranged in regu- 
lar, overlapping rows; the arrangement be- 
ing as regular as that of the scales on a fish 
or of the shingles on a roof (Fig. 323). In 
the upper part of the figure the membrane 
is represented with the scales removed. 

The chief use of the scales on the body is for the protection of the 
insect. Another use of the scales may be to strengthen the wings. 
A secondary use of the scales is that of ornamentation; for the beautiful 
colors and markings of the moths and butterflies are due to the scales. 
If the scales are removed the colors of the insects are destroyed. 

The mouth-parts of moths and butterflies are especially adapted for 
sucking nectar from flowers. If the head of a butterfly be examined, 

* Lepidfiptera : lepido {\tirls, \inl5os), scale; pteron (irrepov), a wing. 

183 


t a- s A -£-*-" ■ 


slmAArtJFJf: 


Fig. 323. — Part of wing of butterfly, 
greatly magnified. 


184 


THE STUDY OF INSECTS 


Fig. 324. — Maxillae of cotton-moth, and tip of same enlarged. 


Fig. 325. — Cross-section of maxillae. 


there will be found a long sucking tube, which when not in use is coiled 
on the lower side of the head between two forward-projecting appendages. 
This long sucking tube is composed of the two maxillae, greatly elongated, 

and fastened together side by 
side. In Figure 324 there is 
represented a side view of the 
maxillae of a moth; and in 
Figure 325 a cross-section of 
these organs. Each maxilla is 
furnished with a groove, and 
the two maxillae are so fastened 
together that the tw r o grooves 
form a tube through which 
the liquid food is sucked. As 
a rule the maxillae of insects 
of this order are merely fitted 
for extracting the nectar from 
flow r ers, but sometimes the tips 
of the maxillae are armed with 
spines, as shown in Figure 324. 
This enables the insect to 
lacerate the tissue of ripe fruits 
and thus set free the juice, 
which is then sucked up. 
Many moths do not eat in 
the adult state ; with these the 
maxillae are wanting. The two forward projecting organs between which the 
maxillae are coiled when present are 
the labial palpi. In some moths the 
maxillary palpi are also developed. 
The larvae of Lepidoptera are 
known as caterpillars. They vary 
greatly in form and appearance; 
but are usually cylindrical, and pro- 
vided with from ten to sixteen legs, 
— six thoracic legs, and from four 
to ten abdominal legs. The thoracic 
legs, which are finally developed 
into the legs of the adult, have a 
hard external skeleton; and are 
jointed, tapering, and armed at the 
end with a little claw. The abdom- 
inal legs, which are shed 
with the last larval skin, 
are thick, fleshy, without 
joints, elastic or contrac- 
tile, and are generally 
furnished at the extrem- 
ity with numerous, min- 
ute hooks (Fig. 326); they are termed prologs. 

Most caterpillars, except the larvae of nearly all butterflies, spin 
cocoons (Fig. 327). In some instances, as in case of the silkworms, a 


Fig. 326. — Larva of a hawk-moth. 


LEPIDOPTERA 


185 


great amount of silk is used in the construction of the cocoon; in others 
the cocoon is composed principally of the hairs of the larva, which are 
fastened together with a fine web of silk. 


Fig. 328. — Pupa of a moth. 


Fig. 327. — Cocoon of a moth. 

The pupae of the Lepidoptera are typically of the obtected type; that 
is, the developing wings, legs, mandibles, maxilla?, and antennae are 
glued to the surface of the body (Fig. 
328); but in some of the more general- 
ized forms these appendages are free. 

The members of this order as a rule 
feed upon plants, and are not aquatic; 
some, as the clothes-moth and the species 
that destroy scale-insects, feed on animal 
matter, and a very few feed upon plants 
below the surface of the water. 

More than nine thousand species of Lepidoptera are known to occur 
in America, north of Mexico. These represent more than sixty families. 

We commonly divide the Lepidoptera into two groups; the moths 
and the butterflies. There is, however, a group within the division of 
butterflies known as the skippers, which constitutes a fairly well-defined 
assemblage of forms. 

The moths. • — These are the insects commonly called millers. 
Most of the species fly by night and are frequently attracted to lights. 
When at rest the wings are either wrapped around the body, or are 
spread horizontally, or are folded roof -like on the abdomen; except in a 
few cases they are not held in a vertical position above the body. The 
antennae of moths are of various forms; they are usually thread-like or 
feather-like; only in rare cases are they enlarged towards the tip. 

The butterflies. — All of our species of butterflies fly in the daytime; 
and, with few exceptions, they fold the wings together above the back in 
a vertical position when at rest. The antennae are thread-like, and 
usually with a club at the tip. It was this feature that suggested the 
term Rhopalocera, which is applied to them. 

The group of butterflies as defined here includes the representatives of 
two quite distinct superfamilies, the Hesperioidea or skippers, and the 
Papilionoidea or true butterflies. 

The skippers are so called on account of their peculiar mode of flight. 
They fly in the daytime and dart suddenly from place to place. When at 
rest they usually hold the wings erect in a vertical position like the true 
butterflies; often the fore wings are thus held while the hind wings are 
extended horizontally. The antennae are thread-like, and enlarged to- 


1 86 THE STUDY OF INSECTS 

wards the tip ; but in most cases the extreme tip is pointed and recurved, 
forming a hook. The abdomen is usually stout, resembling that of a 
moth rather than that of a butterfly. 

CLASSIFICATION OF THE LEPIDOPTERA 

The first step to be taken in the study of the classification of these 
insects is to become thoroughly familiar with the nomenclature of the 
wing veins; this is given on pages 32 to 33. It is a good plan to take 
several of the larger moths and butterflies and make drawings showing 
the courses of the veins of the wings in each, carefully indicating the 
names of the veins on the drawings. 

As the scales on the lower surface of the wings are more closely ap- 
plied to the wings than are those on the upper surface, the veins can be 
best seen when the wings are examined from below. The veins can be 
rendered more distinct for a few seconds by putting a little 95 % al- 
cohol or benzol on the part of the wing to be examined; this can be 
easily done by means of a camel's-hair brush. 

Sometimes it is necessary to remove the scales from a small part of 
the wing in order to determine the nature of some characteristic; this 
can be easily done by scratching them off lightly with a pin on the under- 
side only. 

The above methods are all that are needed in the majority of cases 
where the mere determination of an insect is the object. But when a 
very careful study of the venation of a wing is to be made, it should be 
bleached and mounted on a card or on a glass slip in order that it may 
be studied with a compound microscope. The following is the method of 
bleaching wings : — 

1. Remove the wings carefully so as not to break the frenulum if 
there be one. 

2. Dip the wings in alcohol in order to wet them. 

3. Immersion for an instant in hydrochloric acid, one part acid to 
nine parts water, will help but usually not necessary, 

4. Put them in Labaraque solution and leave there till the color has 
been removed from the scales. If a wing bleaches slowly, the process 
can be hastened by dipping it in the dilute acid and returning it to the 
Labaraque solution from time to time. This solution can be procured of 
most druggists. It deteriorates if left exposed in strong light. If it can- 
not be obtained, use an aqueous solution of chloride of lime. 

5. When a wing is bleached put it in alcohol and leave it there three 
to five minutes. This is to wash off the Labaraque solution. The wing 
can then be mounted on a card. But it is better to mount it as described 
below. 

6. Put wing on slide in alcohol, blot off excess alcohol, add a drop or 
two of oil of lavendar, let stand several minutes, put on balsam and 
cover with thin glass. 

Wings bleached and mounted in this way make an important addition 
to a collection. The slides should be carefully labelled to correspond with 
the rest. 

There are a few special terms used in describing the wings of the 
Lepidoptera which should be learned : — 

Frenulum. — In most moths there is a strong spine or a bunch of 


LEPIDOPTERA 


187 


bristles borne by the hind wing at the humeral angle (Fig. 329, /); this 
is the frenulum. Its use is to insure the acting together of the two wings 
of one side. As a rule the frenulum of the male consists of a single 
strong spine and that of the female when present of two or more bristles. 

Jugum. — In one suborder, including only a few rare moths, there 
exists, instead of a frenulum, a lobe borne near the base of the inner 
margin of the fore wing (Fig. 333, p. 193) ; this is the jugum. See suborder 
Jugatse. 


/?, *, 


/?, ^ 


Fig. 32g. — Wings of a moth: J h, frenulum-hook. 


Fig. 330. — Wings of Hemerocampa leucostigma. 


Discal cell. — Near the centre of the basal part of the fore wing there 
is a large cell lying between veins R and Cu (Fig. 330); this is the 
discal cell. In the more generalized Lepidoptera this cell is divided into 
two parts by the base of vein M (Fig. 330, hind wing); in such cases the 
cell lying immediately behind vein R is cell R, and that lying immedi- 
ately behind vein M is cell M. 

Patagia. — At the base of each fore wing there is a scale-like ap- 
pendage; these are the patagia or tegulae. 

In descriptions of Lepidoptera reference is often made to the palpi. 
These form the double beak-like projection which extends forward from 
the lower surface of the head. In most Lepidoptera only the labial 
palpi are well developed; but in some of the more generalized forms the 
maxillary palpi are also present. 

The presence or absence of ocelli is a character which is sometimes of 
considerable importance. These organs are situated, one on each side, 
above the compound eye and near its margin. But it requires some skill 
to find them when they are present, on account of the long scales clothing 
the head. 

The eye cap is also a character of some importance. The first seg- 
ment of the antennas of some moths is much broadened and hollowed out 


188 THE STUDY OF INSECTS 

and when such moths are at rest with the antennae folded back this seg- 
ment covers the eye like a cap. 

SIMPLIFIED KEY TO FAMILIES TO LEPIDOPTERA* 

A. Hind wing with eleven veins (counting along the margin) besides anals. 

B. Expanse' over i inch; mouth-parts rudimentary, p. 192 Hepialid^e 

BB. Expanse about .'. inch; mouth-parts functional. 

C. Mouth-parts for biting; middle tibia unarmed, p. 192 . . . . MlCROPTERYGIDjE 
CC. Mouth-parts for sucking (the usual spiral tongue), middle tibia ending in a 

single spur. p. 192 Eriocraniidje 

AA. Hind wing with only seven veins (or less) besides anals. 

B. Membrane of hind wing lanceolate or linear, narrower than its own fringe. 
C. First joint of antenna? very large and spoon shaped, completely covering the 
eye when folded back (an "eye-cap"). Cell of fore wing at least fully 
formed; palpi rudimentary, drooping, apex of fore wing sharply bent up or 

down. p. 202 Lyonetiid/E 

CC. No eyecap. 

D. A row of bristles on outer side of labial palpus (besides the usual hair and 
scales). Maxillary palpi usually conspicuous at base of tongue (between 
labial palpi), and folded, but absent in common clothes-moth. Head very 
rough. 
E. Wing-membrane with microscopic spinules between the sockets of the 
scales; female with piercing ovipositor; Sc of hind wing usually ap- 
parently forked into equally stout branches at base, or very stout; 
antenna smooth-looking (either with both rows of scales on each seg- 
ment lying flat, or finely pubescent) or else longer than fore wing. p. 195 

InCURVARIIDjE 

EE. Wing-membrane not spinulated; female with an extensible, tubular, 
soft and hairy ovipositor; Sc of hind wing apparently simple, connected 
by a weak vein to base of R or none; antenna with outer whorl of 
scales on each segment usually raised; rough-looking, not longer than 

fore wing. p. 199 Tineid^e 

DD. No bristles distinct from the usual hair and scales. Maxillary palpus 
inconspicuous, or projecting straight forward. 
E. Fore tibia without an epiphysis (antenna-cleaner) on its inner face. p. 204. 

COLEOPHORID^E 

EE. Fore tibia with an epiphysis along its middle part. 

F. Fore wing with four veins running from discal cell to costa, and five 

or six to below apex (inner margin), p. 207 Yponomeutid/E 

FF. Fore wing with at least as many veins running to costa as to inner 
margin from discal cell. 
G. Hind tibia hairy above; cell of fore wing very large, with an ac- 
cessory cell cut off from it by a weak vein. p. 202 . .Tischeriid^e 
GG. Hind tibia smooth-scaled, or with a regular series of bristles; 
cell of fore wing narrow, accessory cell (1st R3) not distinguishable. 

p. 203 Gracilariid/e 

BB. Hind wing (membrane) notched below apex, frequently narrower than its own 

fringe, p. 206 Gelechiid,e (part) 

BBB. Hind wing divided in 3 feathers, p. 217 Pterophorid^e 

BBBB. Hind wing broad, not notched, and broader than its own fringe. 
C. Antennae swollen toward tip (clubbed), no frenulum. 

D. Bases of antenna? separated by a space wider than their own thickness, 

fore wing with all branches of R, M, and Cu, (10 in all) present and arising 

separately from discal cell. 

E. Large butterflies, thorax much wider than head. p. 258. . . MEG ATH YMIDjE 

EE. Medium or small butterflies, expanding rarely over 2 inches; head 

wider than body. p. 259 Hesperiid/E 

DD. Antenna? closer together at base, branches of R partly stalked or united, 

there being only 9 (usually 8 or less) veins arising separately from discal 

cell. 

E. Fore wing with 3d A short and curved but running down free to inner 

margin, hind wing with only I anal. Cu apparently 4-branched. p. 262. 

PAPILIONID.E 

* This key was drawn up by Dr. W. T. M. Forbes. 


' LEPIDOPTERA 189 

EE. Fore wing without a free 3d A, hind wing with 2 anal veins. Cu (in 
our species) apparently 3-branched. 
F. Fore legs normal in size, used for walking. Usually 1 radial vein lost. 
G. M2 arising from middle of end of discal cell. Head very narrow, the 

antennae slightly encroaching on the eye. p. 281 Lyc^enid^e 

GG. M2 arising from upper angle of discal cell or even (usually) 
stalked with R3-5. Head wider, the eye a complete circle, p. 265. 

Pieridae 

FF. Fore legs reduced, often brush-like (except some 9's), not used for 
walking. Fore wing with all veins (except 1st A and 3d A) almost 

always preserved, p. 268 Nymphalid^e 

CC. Antennas not swollen toward tip, or if so (Sphingidae, Agaristidas, etc.) with 

frenulum well developed. 

D. Hind wing with Sc and R closely parallel or fused beyond where R leaves 

the discal cell. (Closer than they are along the discal cell); base of M 

not preserved in cell. 

E. Wings long and narrow, fore wing 4 x as long as wide; wings interlocked 

by rows of spines near inner edge of fore wing and costa of hind wing. 


p. 207 


. .^GERIID/E 


EE. Wings relatively broader, hind wing but little longer than broad. 
Wings not interlocked. 
F. Hind wing with three anal veins, 1st A being preserved, p. 212. 

Pyralidid^e 

FF. Hind wing with 1 or 2 anal veins. Body extremely stout, projecting 

far beyond the wings which are narrow, p. 218 Sphingidae 

DD. Hind wing with Sc and R widely separated beyond end of discal cell 

(Sc rarely wholly lost) ; or (some Cossidae) with base of M fully preserved, 

forked in cell. 

E. Fore wing with M2 arising more than one-third of the distance from M3 to 

M 1 , so that Cu appears to be 3-branched. 

F. Hind wing with Sc and R touching, closely parallel or fused no 

second quarter of discal cell, then diverging before end of discal cell. 

G. Base of Sc sharply angled, and connected by a more or less distinct 

humeral vein to base of frenulum. Usually slender moths, p. 223. 

Geometridae 

GG. Sc gently curved at base, not connected to frenulum-base. Stout 
moths. 
H. Radius pectinate (with Ri, 2, 3, 4 given off successively from the 
stem that leads to R5); frenulum rudimentary, p. 255. . Bombycid^e 
HH. R3 and 4 most closely associated; frenulum functional, con- 
spicuous in male. p. 227 Notodontid^e 

FF. Sc and R of hind wing diverging sharply almost from base. 

G. Hind wing with- two anal veins, upper discocellular vein (the portion 
of vein bounding the discal cell between the points where R s 

and Mi leave it) short and transverse, p. 246 Citheroniid.e 

GG. Hind wing with only one anal vein or upper discocellular vein 

long and longitudinal (usually both), p. 249 Saturniid,e 

EE. Fore wing with M2 associated with Cu-stem, Cu therefore apparently 
4-branched. 
F. Sc and R of hind wing fused for second fourth of discal cell or more. 
G. Vein 1st A preserved in both wings. 

H. Wings light colored, tongue absent, p. 197 Megalopygidae 

HH. Wings largely blackish, tongue strong, p. 197. . . Pyromorphid/E 
GG. Vein 1st A lost in both wings (fore wing with 1 anal, hind wing 

with two) . p. 242 . Arctiim: 

FF. Sc and R more shortly fused, or not at all. 

G. Vein 1st A, preserved in one and usually both wings. 

H. Vein 1st A, a well-marked tubular vein (i.e., an ordinary vein) 

on fore wing, at least toward margin. 

I. Spurs of tibiae longer than width of tibia;, normally over twice as 

long, if somewhat shorter with base of media (in cell) simple, 

dividing the cell into two parts. 

J. Fore wing with R3 and 4 stalked (forking over apex) or 

united, in the latter case with only two radial veins running 


1 9 o THE STUDY OF INSECTS 

to costa, and the third preserved vein to the apex.* p. .198 

ElCLEID/E 

JJ. pure wing with all veins preserved and separate, or with R4 
and 5 stalked or united, in that ease with three veins running 
to co ta before the one thai goes to apex. 
K. Fore wing with R5 running to costa. 

L. Palpus upturned and sickle-shaped, with long, pointed 

third joint, p. 205. (in part) CEcophorid^e 

LL. Palpus with third joint blunt, and either projecting 
forward or very short. 
ft 1 . Cu2 arising not far from middle of inner margin of 
cell; palpus without bristles (Peronea) p. 209. 

TORTRICIDjE 

MM. C112 arising more than I way out on cell; palpus 
normally with stiff bristles on outer side of second 
joint, p. 199, 195 . . . . Tineid^e and Incurvariid^e 
KK. Fore wing with R5 running to outer margin below apex. 
L. Fore wing with R4 and 5 strongly stalked or united (one 
vein missing); hind wing with R and Mi widely sepa- 
rated at origin from cell; palpus upturned, sickle-shaped, 
with third joint long and pointed, p. 205 

(Ecophorid^e (part) 

LL. Fore wing with R4 and 5 separate at origin or (rarely) 

with them stalked, but with R and Mi of hind wing 

stalked or closely approximate at origin; palpus with 

third segment usually short and blunt. 

M. Head smooth; palpus closely scaled, the third joint 

usually upturned and continuing the curve of the 

palpus; base of M (in cell) rarely preserved, and if 

so, bisecting cell. p. 207 Yponomeutid^e 

MM. Head and palpus rough-scaled, the third joint 
projecting forward, or stumpy and well set off; base of 
M running diagonally, in its outer part close to hind 

margin of cell, rarely lost. p. 209 Tortricid^e 

II. Spurs of tibia rudimentary, or if about as long as width of 
tibia, with M forked in cell. 
J. Base of M forked in cell, enclosing an intercalated cell (1st 

M2); spurs of tibiae distinct, p. 196 Cossid^e 

JJ. Base of M simple, dividing the cell in two parts. Tibiae 

normally with spurs absent, p. 200 Psychid^e 

HH. Vein 1st A, absent in fore wing. Palpus sickle-shaped, usually 

smooth, with long, pointed third joint, p. 205 GelechiiDjE 

GG. Vein 1st A, lost in both wings. 
H. Frenulum present. 

I. "Micros" (wings soft and loosely scaled) fringe lengthened at 

anal angle of hind wing, hind wing with Ri preserved as a 
strong vein connecting Sc and R near base, and palpi long and 
sickle-shaped, p. 205 Gelechiid/e 

II. "Macros" (wings strong) fringe hardly longer at anal angle 
of hind wing, Ri of hind wing lost by fusion of Sc and R or 
else palpi very short. 

J. Ocelli absent, hind wing with Sc and R merely touching J to 
I way out on discal cell or entirely separate, p. 232. 

Lymantriid^e 

JJ. Ocelli present (easily visible behind eye without denuding) 
Sc and R fused a short distance, or touching much nearer to 
base. 

K. Antennae swollen toward apex. p. 241 Agaristid^e 

KK. Antenna; regularly tapering, p. 234 NoctuiDjE 

HH. Frenulum absent, p. 256 Lasiocampid/E 

* If the wing is bluntly rounded the middle of the curving tip is viewed as the apex. 


LEPIDOPTERA 


191 


THE MOTHS 

There are thousands of species of moths many of which are commonly 
known as millers. Most of them are nocturnal in their activities and 
frequently come to lights in large numbers. When the individuals are at 
rest the wings are nearly always either wrapped around the body, or are 
spread horizontally, or are folded roof-like on the abdomen. Although 
the antennas are of various forms, they are usually thread-like or feather- 
like and only rarely are they enlarged at the tip. 

Suborder JUGATE 

The Jugate Lepidoptera 

The American representatives of this suborder are rare moths, which 
the student beginning the study of insects is not likely to meet. They 
can be easily recognized by the peculiar structure of the hind wings, 
which resemble the fore wings in form and in venation (Fig. 331). Inall 
other Lepidoptera, the two pairs of wings differ in form, and the hind 
wings are furnished with fewer veins than are the fore wings. 


Fig. 331. — Wings of Micropteryx. 

The most important character of the suborder, and the one to which 
its name refers, is the organ which aids in holding the two wings of each 
side together. There projects backward from the inner margin of the 
fore wing near its base a small lobe (Fig. 331, /), which extends, under or 
over the costal margin of the hind wing; while the greater part of the 
inner margin of the fore wing overlaps the hind wing. This arrangement 
assures the acting together of the two wings, at least in the downward 
stroke. 

This projecting lobe in its typical form is named the jugum or yoke; 
and the moths possessing this projection are termed the Jugatae or the 
Jugate Lepidoptera. 

The suborder Jugatas, as now more commonly limited, includes several 
families, representatives of three of which have been found in America; 
these are the Micropterygidae. the Eriocraniidae, and the Hepialidas. 


i 9 2 THE STUDY OF INSECTS 

Family Micropterygid^e 
The Mandibulate Jugatcs 

The members of this family are small insects which resemble tineid 
moths in general appearance. As with other members of the suborder 
Jugatae, the venation of the hind wings closely resembles that of the fore 
wings (Fig. 331). But these insects differ from all other Lepidoptera in 
that the adult moths have well-developed and efficient mandibles. This 
remarkable character, together with the lack of certain internal organs, 
has caused some authorities to take these moths out of the Lepidoptera 
and to put them in a separate order. 

The abdomen of the female has ten segments but there is no oviposi- 
tor. The adults feed on pollen. The larva? of our American forms do 
not seem to have been observed. 

Family Eriocraniid^e 
The Haustellate Jugates 

The members of this family, like those of the preceding one, are small 
insects which resemble tineid moths in general appearance. In this 
family the mandibles of the adult are vestigial; the maxilla? are formed 
for sucking, each maxilla forming half of a long sucking-tube, as in higher 
Lepidoptera; and the females have a piercing ovipositor. The jugal 
lobe of the fore wing extends back above the base of the hind wing and 
is clasped over an elevated part of the hind wing, thus being of the type 
described as a fibula. 

The best known species, Mnewomca auricyanea, is gold with purple 
spots and has a wing-expanse of about \ an inch. The larva mines in 
the leaves of chestnut, oak and chinquapin, making a large blotch mine. 
When grown it goes into the ground, spins a cocoon and changes to a pupa 
in the following winter. 

The pupa has long, arm -like toothed mandibles, with which it cuts 
the tough cocoon and with which it digs its way up to the surface of the 
ground; the adult emerges in April. 

Family Hepialid^e 
The Swifts or the Macrojugata, 

The members of this family are of medium or large size. Figure 332 
represents in natural size one of the larger of the American species, but 
many exotic species are larger than this one. Our smaller species have a 
wing-expanse of at least one inch. Our best-known species are brown or 
ashy-gray in color, with the wings marked with silvery-white spots. 

It is said that these moths fly near the earth, and only in the evening 
after sunset, hiding under some low plant, or clinging to the stalk of an 
herb during the day. Some of them fly with extreme rapidity, with an 
irregular mazy flight, and have, therefore, been named swifts by col- 
lectors. 

In the Hepialidae the posterior lobe of the fore wing is a slender. 


LEPIDOPTERA 


i93 


finger-like organ, which is stiffened by a branch of the third anal vein, 
and which projects beneath the costal margin of the hind wing. As 


Fig. 332. — Sthenopis purpurascens. 


the greater part of the inner margin of the fore wing overlaps the hind 
wing, the hind wing is held between the two. This is the type of pos- 
terior lobe of the fore wing to which the term jugum is applied (Fig. 333). 


Fig. 333. — Wings of a hepialid, seen from below; a, accessory vein. 

The larvae are normal caterpillars and furnished with sixteen legs; 
they feed upon wood or bark, and are found at the roots or within the 
stems of plants. They transform either in their burrows, or, in the case 
of those that feed outside of roots, within loose cocoons. The pupae have 
transverse rows of teeth on the abdominal segments; these aid them in 
emerging from their burrows. 

This family is represented in our fauna by two genera, Hepialus and 
Sthenopis. 


194 


THE STUDY OF INSECTS 


Suborder FRENAT^ 

The members of the Frenatae arc most easily recognized by the fact 
thai the venation of the hind wings (lifters markedly from that of the 
fore wings, being much more reduced. In this suborder, vein Ri of the 
hind wings coalesces with subcosta, the two appearing as a single vein, 
except that, in some cases, a short section of the base of Ri is distinct 


5r__£i__£ 


Fig. 334. — Wings of Prionoxyslus robinicB. 

presenting the appearance of a cross-vein between radius and subcosta 
(Fig. 334. Ri)-. 

The essential characteristic of the Frenatas is that they are de- 
scendants of those primitive Lepidoptera in which the two wings of each 
side were united by a frenulum. This fact should be clearly understood, 
for in many of the Frenatas the frenulum has been lost. The loss of the 
frenulum in these cases is due to its having been supplanted by a substi- 
tute for it, by an enlarged humeral area of the hind wings, which causes 
the two wings of each side to overlap to a great extent. This overlapping 
of the two wings insures their synchronous action; and the frenulum, 
being no longer needed for this purpose, is lost. 

As a rule the frenulum of the female, when present, consists of several 
bristles, while that of the male consists of a single strong, spine-like 
organ . 

The frenulum-hook, which is present in the males of most moths, is a 
membranous fold on the lower surface of the fore wing for receiving the 
end of the frenulum, and thus more securely fastening the two wings 
together (Fig. 329, / /?). As a rule, the frenulum hook arises from the 
membrane of the wing near the base of cell C. 


LEPIDOPTERA 


i95 


Leaf infested by the maple-leaf 


Family Incurvariid^e 

An interesting representative of the family Incurvariidae is the maple- 
leaf cutter, Paraclemcnsia acerijoliella. The larva infests the leaves of 
maple, and occasionally is so abundant 
that it does serious injury. The larva is at 
first a leaf-miner, but later it is a case-bearer. 
The leaves of an infested tree present a 
strange appearance (Fig. 335). They are 
perforated with numerous elliptical holes, 
and marked by many, more or less perfect, 
ring-like patches in which the green sub- 
stance of the leaf has been destroyed but 
each of which incloses an uninjured spot. 
These injuries are produced as follows: 
the larva, after living for a time as a leaf- 
miner, cuts an oval piece out of a leaf, 
places it over its back, and fastens it down 
with silk around the edges. This serves 
as a house beneath which it lives. As it 
grows, this house becomes too small for it. 
It then cuts out a larger piece which it 
fastens to the outer edges of the smaller 
one, the larva being between the two. 
Then it crawls halfway out upon the leaf, and by a dexterous lifting of the 
rear end of its body turns the case over so that the larger piece is over its back. 
When it wishes to change its location it thrusts out its head and fore legs 
from the case and walks off, looking like a tiny turtle. When it wishes to eat, 
it fastens the case to the leaf and, thrusting its head out, eats the fleshy part 
of the leaf as far as it can reach. This explains the circular form of the 
patches, the round spot in the center indicating the position of the case. 
The insect passes the winter in the pupa state within its case, which falls to the 
ground with the infested leaf. The moth is of a brilliant steel-blue or bluish- 
green color, without spots but 
with an orange-colored head; 
it appears in early summer. 

The yucca moth, Tegeticula 
alba, is another interesting 
member of this family. This 
species infests Yucca filamen- 
tosa, a plant not fitted for self- 
pollination or for pollination by 
insects in the ordinary ways ; in 
fact, it is pollinized only by 
moths of the genus Tegeticula, 
the larvae of which feed on its 
seeds. This is one of the few 
cases in which a particular plant 
and a particular insect are so 
specialized that each is dependent upon the other for the perpetuation of the 
species. In the female moth, the maxillae are each furnished with a long, 
curled, and spinose appendage, the maxillary tentacle (Fig. 336), fitted for the 


Fig. 336. — Tezeticula alba: a, side view of head and neck 
of fern ile denuded; i, load of pollen; 2, maxillary tentacle; 
.?, maxillae; 4, maxillary palpi; 5, antennae; b, maxillary ten- 
tacle and palpus. All enlarged. (From Riley.) 


i 9 6 THE STUDY OF INSECTS 

collection of pollen. After collecting a large load of pollen, often thrice as 
large as the head (Fig. 336), the female moth places her eggs, by means 
of her long, extensile ovipositor, into an ovary, usually of another flower 
than that from which the pollen was collected. After oviposition, the 
moth runs up to the tip of the pistil and thrusts the pollen into the 
stigmatic opening. Thus is insured the development of seeds, upon which 
the larvae hatched from the eggs placed in the ovary are to feed. As 
many more seeds are developed than are needed by the larvae, the per- 
petuation of the yuccas is assured. 

The full-grown larva leaves the yucca pod and makes its way to the 
ground, where it spins a dense cocoon several inches below the surface. 
The adult moth has a wing-expanse of about 1 inch. The wings are silvery- 
white above. 

Family Cossid^e 

The Carp enter -moths 

This family includes moths with spindle-shaped bodies, and narrow, 
strong wings, some of the species resembling hawk-moths quite closely 
in this respect. The larvae are borers; many of them live in the solid 
wood of the trunks of trees. The wood-boring habits of the larvae suggest 
the popular name carpenter-moths for the insects of this family. 

These moths fly by night and lay their eggs on the bark of trees, 
or within tunnels in trees from which adult carpenter-moths have 
emerged. The caterpillars are nearly naked, and, although furnished with 
prolegs as well as true legs, are grub-like in form. The pupa state is 
passed within the burrow made by the larva. When ready to change 
to an adult, the pupa works its way partially out from its burrow. This 
is accomplished by means of backward-projecting saw-like teeth, there 
being one or two rows of these on each abdominal segment. After the 
moths have emerged, the empty pupa-skins can be found projecting from 

the deserted burrows. 

The carpenter-moths 
are of medium or large size. 
The antennae of the males 
are mostly bipectinate ; 
those of the females are 
either very slightly bipect- 
inate or ciliate. In a few 
species the antennae are 
lamellate. The ocelli are 
wanting, and the maxillae 
are vestigial. See Figure 
334 for type of venation. 
The locust-tree car- 

Fig 337. — Prtonoxvstus rohmur, female. , . „ 

penter-moth , Frionoxystus 
roblnice. — Figure 337 represents the female, natural size. The male is 
but little more than half as large as the female. It is much darker than 
the female, from which it differs also in having a large yellow spot, which 
nearly covers the outer half of the hind wings. The moths fly in June 
and July; the larvae bore in the trunks of locust, oak, poplar, willow, 


LEPIDOPTERA 197 

and other trees. It is supposed that the species requires three years to 
complete its transformations. It is found from the Atlantic Coast to 
California. 

The lesser oak carpenter-worm, Prionoxystus macmurtrei. — This is 
a slightly smaller species than the preceding. The larva bores in the 
trunks of oak in the East. The moth has thin, slightly transparent 
wings, which are crossed by numerous black lines. The male is much 
smaller than that of P. robinice, and lacks the yellow spot on the hind 
wings. 

The leopard-moth, Zeuzera pyrina. — This species is white, spotted 
with numerous small, black spots, which suggested its common name. 
The adult has a wing-expanse of from i| to 2 inches. It is a European 
species, which was first observed in the vicinity of New York City in 
1882; since that time it has spread to other parts of the East. The 
larva is a very injurious borer in many species of trees and shrubs. The 
young larvae bore in the small twigs; later they migrate to larger limbs 
or to the trunk. 

Family Pyromorphid^e 
The Smoky-moths 

There are but few insects in our country pertaining to this family; 
only fifteen species are now recognized, but these represent six genera. 
These are small moths, which are chiefly of a smoky-black color; some 
are marked with brighter colors; the wings are thinly scaled; and the 
maxillae are well developed. The larvae are clothed with tufted hair; 
they have five pairs of prolegs, which are provided with normal hooks. 

The grape-leaf skeletonizer, Harrtstna americdna, is a well-known 
member of this family which is widely distributed throughout the eastern 
United States from New England to Florida and 
westward to Missouri and Arizona. 

The wings of this moth are long and narrow 
(Fig. 338) ; the abdomen- is long, and widened 
towards the caudal end. It is greenish -black in 
color, with the prothorax reddish-orange. The 
larva feeds on the leaves of grape and of the Vir- . fig. 338. — Harrisina amer- 
ginia creeper. An entire brood of these larvae will 

feed side by side on a single leaf while young. This species rarely be- 
comes of economic importance. 

Family Megalopygid^; 

The Flannel-moths 

In this family the wings are heavily and loosely scaled, and mixed 
with the scales are long, curly hairs; these give the wings the appear- 
ance of bits of flannel. It is this that suggested the common name of 
these moths. The body is stout and clothed with long hairs. In these 
moths the maxillae are vestigial. The larvae are remarkable for the pos- 
session of seven pairs of prolegs ; these are borne by abdominal segments 
2 to 7 and 10; but those of segments 2 and 7 are without hooks. The 


ig8 


THE STUDY OF INSECTS 


Fig. 339. — Lagoa crispala, male. 


setiferous tubercles bear large numbers of fine setae; so that the body is 
densely hairy; and interspersed among the fine setae are venomous setae. 

The crinkled flannel-moth, Lagoa cris- 
pata, is cream-colored, with the fore wings 
marked with wavy lines of crinkled black 
and br< iwnish hairs. The male is represented 
in Figure 339; the female is larger, expand- 
ing i\ inches. In the female the antennae 
are very narrowly pectinate. 

The larvae feed on many trees and shrubs, 
including oak, elm, apple, and raspberry. 
They are short, thick, and fleshy, and are 
covered with a dense coat of long, silky, brown hairs, which project up- 
ward and meet to form a ridge or crest along the middle of the back; 
interspersed among these fine hairs are venomous setae. 

The cocoons are of a firm, parchment-like texture, covered with a 
thin web of rather coarse threads. Mixed with the silk of the cocoon are 
hairs of the larva. The cocoon is similar to that of the next species. 

The puss-caterpillar moth, Megalopyge opercular is, is somewhat 
smaller than the preceding one; the male has a wing-expanse of about 
1 inch and the female of about \\ inches. The 
fore wings are umber-brown at base, fading to 
pale yellow outwardly; they are marked with 
wavy lines of white and blackish hairs, and the 
fore margins are nearly black. The larvae are sim- 
ilar to those of the preceding species. The cocoon 
is provided with a hinged lid (Fig. 340). 

This species is found from North Carolina 
to Texas. The larva is a very general feeder; 
it is often found on oak. It is a seriously nettling ° penu ans ' 
caterpillar often causing distinct irritation when it comes in contact with 
one's skin. 


Fig. 340. — ■ Old cocoon of Megalo- 


Family Eucleid^ * 
The Slug-caterpillar Moths 

One often finds on the leaves of shrubs or trees, elliptical or oval 
larvae that resemble slugs in the form of the body and in their gliding 
motion. As these are the larvae of moths they have been termed slug- 
caterpillars; but they present very little similarity in form to other 
caterpillars. The resemblance to slugs is greatly increased by the fact 
that the lower surface of the body is closely applied to the object upon 
which the larva is creeping, the thoracic legs being small and the prolegs 
wanting. There is, however, on the ventral side of the abdomen a series 
of sucking-disks, which serve the purpose of prolegs. The head of the 
larva is small and retractile. In some species the body is naked; in 
others it is clothed with tufts of hair; and in others there is an armature 
of branching spines. Several species bear venomous setae. 

The larwe when full-grown spin very dense cocoons of brown silk; 

* This family is termed the Cochlidiidac by some writers, and by others the 
Limacodidae. 


LEPIDOPTERA 


IQQ 


Fig. 341. 

species 


these are egg-shaped or nearly spherical, and are furnished at one end 
with a cap which can be pushed aside by the adult when it emerges 
341). The cocoons are usually spun between leaves. 

The moths are of medium or small size; the 
body is stout, and the wings are heavily and loosely 
scaled. The maxillae are vestigial. These moths 
vary greatly in appearance, and many of them are 
very prettily colored. 

The following are some of the better known 
of this family. 

The saddle-back caterpillar, Siblne stimulea. — This larva 
can be recognized by Figure 342. Its most characteristic 
feature is a large green patch on the back, resembling a saddle- 
cloth, while the saddle is represented by an oval purplish-brown spot. 
The moth is dark, velvety, reddish-brown, with two white dots near the 
apex of the fore wings. The larva feeds on oaks and other forest trees. 
This is one of the species that are armed with venomous setae. 

The spiny oak-slug, Euclea delphinii. — This larva (Fig. 343) is one of 
the most common of our slug-caterpillars and one of those that are armed 
with venomous setae. It feeds on the leaves of oak, pear, willow, and 
other trees. The moth (Fig. 344) is cinnamon-brown, with a variable 
number of bright green spots on the fore wings. 


Fig. 342.— .S7- 
bine stimulea, 
larva. 


Flo. 343. — Euclea del- 
phinii, 1 rva. 


Fig. 344. — Euclea del- 
phinii. 


Fig. 345. — Phnbelrnn pithe- 
cium, larva. (After Dyar.) 


The hag-moth, Phobetron pithecium. — The common name hag-moth 
is applied to the larva of this species on account of its remarkable ap- 
pearance (Fig. 345). It bears nine pairs of fleshy appendages which are 
covered with brown hairs. In the full-grown larva the third, fifth, and 
seventh appendages are longest; these are twisted up and back, and 
suggest the disheveled locks of a hag. This larva feeds on various low 
shrubs and the lower branches of trees. At the time of spinning, the 
larva sheds the fleshy processes, and they remain on the outside of the 
cocoon. 


Family Tineid.-e 

The head is usually clothed with erect hair-like scales. The antennae 
are shorter than the front wings. The maxillae are usually small or 
vestigial. The maxillary palpi are usually large and folded. The labial 
palpi are short and clothed with bristles. In the typical genera the 


200 


THE STUDY OF INSECTS 


venation of the wings is quite generalized (Fig. 346), the base of media 
being preserved in both fore and hind wings and all of the veins charac- 
teristic of the Frenatac being 
present ; but in other genera 
the venation is somewhat re- 
duced. 

Many of the larvae are 
case-bearers ; many are scav- 
engers or feed on fungi ; some 
feed on fabrics, especially 
those that contain much 
wool; few if any feed on 
leaves. 

This is a large family. 
More than one hundred 
twenty-five North American 
species are already known; 
fifty of these belong to the 


Fig. 346. — Wings of Tinea parasilella. (After Spuler.) 


genus Tinea. To this family belong the well-known clothes-moths. 

The naked clothes-moth, Tineola biselliclla. — This is our most com- 
mon clothes-moth. Although the larva spins some silk wherever it goes, it 
does not make a portable case; it is, therefore, named the naked clothes- 
moth. But when the larva is full-grown it makes a cocoon, which is 
composed of fragments of its food-material fastened together with silk. 
The adult is a tiny moth with a wing-expanse of from ^ to § inches; it 
is of a delicate straw-color, without dark spots on its wings. 

The case-bearing clothes-moth, Tinea pellionella. — The larva of this 
species is a true case-bearer, making a case out of bits of its food-material 
fastened together with silk. The case is a nearly cylindrical tube open 
at both ends. The pupa state is passed within the case. The adult is a 
small, silky, brown moth, with three dark spots on each fore wing. It 
expands about \ of an inch. 

The tube-building clothes-moth or the tapestry-moth, Trichophaga 
tapetiella. — The larva of this species makes a gallery composed of silk 
mixed with fragments of cloth. This gallery is long and 
winding and can be easily distinguished from the case of 
the preceding species. The pupa state is passed within 
the gallery. The moth differs greatly in appearance from ^M 

the other two species, the fore wings being black from 
the base to near the middle, and white beyond. It 
expands from \ an inch to one inch. 

Family Psychid^e 

The Bag-worm Moths 

The bag-worm moths are so called on account of the 
silken sacs made by the larvae, in which they live and in 
which they change to pupae. In our more conspicuous 
and best-known species the sac is covered either with 
little twigs (Fig. 347) or, in the case of a species that 
feeds on cedar or arbor-vitae, with bits of leaves of these plants. When the 
larva is full-grown it fastens its sac to a twig and transforms within it. 


Fig. 347. — Bag of 
Oiketicus abboti. 


LEPIDOPTERA 


Fig. 348. — Wings of Tkyridopleryx ep/iemertrformis. 


In the adult state the two sexes differ greatly. The female is wingless, 
and in some genera the eyes, antennae, mouth-parts, and legs are vestigial 
or wanting, the body being quite maggot-like. At the caudal end of the 
body there is a tuft of hair-like scales which are mixed with the eggs. 
In most species the female does 
not leave the sac before oviposition 
but deposits her eggs within it. 

The male moths are winged; 
they are small or of moderate size. 
The wings are thinly scaled and 
in some species nearly naked ; when 
clothed with scales they are usually 
of a smoky color without mark- 
ings. The venation of the wings 
varies greatly within the family. 
Figure 3 48 represents the venation 
of our most common species. 

Only about twenty species are 
known from our fauna, of which 
the following are most likely to be 
observed. 

Abbot's bag- worm, Oiketicus 
abboti. — This species occurs in the 
more southern part of our country. 
The larva makes a bag with sticks 
attached to it crosswise (Fig. 347). The adult male is sable brown, with a 
vitreous bar at the extremity of the discal cell of the fore wings; the 
narrow external edging of the wings is pale; the expanse of the wings is 
1 1 inches. 

The evergreen bag- worm, Thyridopteryx ephemera for mis . — This 
species prefers red cedar and arbor-vita?, and for this reason has been 
named the evergreen bag-worm; but it also feeds on many other kinds 
of trees, and as it is the species that is most likely to attract attention, 
and is sometimes a serious pest, it is often called the bag-worm. It is 
our best-known species, and its life-history will serve as an illustration of 
the habits of the members of the family Psychidae. 

The bag of this species is about the same size as that of Abbot's 
bag-worm (Fig. 347) ; but differs in being covered with sprays of leaves 
when it feeds on cedar or arbor-vitse, or with twigs attached lengthwise 
when it feeds on other trees. When full-grown the larva fastens the bag 
to a twig with a band of silk, and then changes to 
a pupa. When the male is ready to emerge, the pupa 
works its way to the lower end of the bag and half- 
way out of the opening at the extremity. Then its 
skin bursts and the adult emerges. The male moth 
has a black, hairy body and nearly naked wings (Fig. 
349). The adult female only partly emerges from the 
pupa skin and awaits the approach of the male. She 
is entirely destitute of wings and legs. The abdomen of the male can be 
greatly extended, making possible the pairing while the female is still in the 
bag. After pairing, the female works her way back into the pupa skin, where 
she deposits her eggs mixed with the hair-like scales from the end of her 


Fig. 340- 
leryx ephemerajormis. 


202 


THE STUDY OF INSECTS 


body. She then works her shrunken body out of the bag, drops to the 
ground, and perishes. The eggs remain in the pupa skin in the sac till 
the following spring. 

Family Tischeriid^e 

Nearly all of our species belong to the genus, Tischeria. The end of 
each narrow front wing is prolonged into a point; the hind wings are 
long and narrow with few veins. The larvae lack thoracic legs and most 
of them make blotch mines in the leaves of oak; but some infest the 
apple, blackbe