[Ill.u.s.tration: FIG. 17.--A Clothes-moth (_Tinea pellionella_)--enlarged.

_a_, adult; _b_, larva; _c_, larva in case.]

"Order HEMIPTERA ([Greek: hemi], half; [Greek: pteron], wing), Bugs. The insects of this order are naturally separated into two great sections; 1st, Half-winged Bugs, or HETEROPTERA ([Greek: heteros], different; [Greek: pteron], wing) having the basal half of the front wings (called _hemelytra_) coriaceous or leathery, while the apical part is membranous. The wings cross flatly over the back when at rest; 2d, Whole-winged Bugs, or h.o.m.oPTERA ([Greek: h.o.m.os], equal; [Greek: pteron], wing), having all four wings of a uniform membranous nature and folding straight down the back when at rest. The latter, if separated, may be looked upon as a Suborder.

[Ill.u.s.tration: FIG. 18.--A Plant-bug (_Euschistus punctipes_).]

"Transformations incomplete; _i. e._, the larvae and pupae have more or less the image of the perfect insect, and differ little from it except in lacking wings.

[Ill.u.s.tration: FIG. 19.--A Soldier-bug (_Milyas cinctus_). _b_, beak enlarged.]

"The genuine or half-winged Bugs (Figs. 18 and 19) are usually flattened in form, when mature; though more rounded in the adolescent stages. They may be divided into Land Bugs (_Aurocorisa_) and Water Bugs (_Hydrocorisa_). The species of the first division very generally possess the power of emitting, when disturbed or alarmed, a nauseous, bed-buggy odor, which comes from a fluid secreted from two pores, situated on the under side of the metathorax. Such well-known insects as the Bed-bug and Chinch-bug belong here. The habits of the species are varied, and while some are beneficial, others are quite injurious to man.

[Ill.u.s.tration: FIG. 20.--A Tree-hopper (_Ceresa bubalus_). _a_, side; _b_, top view.]

"The Whole-winged Bugs (Figs. 20 and 21), on the contrary, are all plant-feeders, and with the exception of a few, such as the Cochineal and Lac insects, are injurious. The secretion of a white, or bluish, waxy, or farinose substance from the surface of the body is as characteristic of this section as the nauseous odor is of the first. It forms three natural divisions, arranged according to the number of joints to the tarsi--namely TRIMERA, with three joints; DIMERA, with two joints; and MONOMERA, with one joint to the tarsi."

Suborder THYSANOPTERA ([Greek: thysanos], a fringe; [Greek: pteron], wing): This suborder contains the single family _Thripidae_, which comprises minute insects commonly known as Thrips, and of which a common species, _Thrips striatus_, is shown in the accompanying figure. (See Fig. 22.) They bear strong relations to both the Pseudoneuroptera and the Hemiptera and by later writers are generally a.s.sociated with the latter order. They feed on plants, puncturing and killing the leaves, or on other plant-feeding species of their own cla.s.s, and are characterized by having narrow wings crossed on the back when at rest, and beautifully fringed, from which latter feature the name of the suborder is derived.

[Ill.u.s.tration: FIG. 21.--A Plant-louse (_Schizoneura lanigera_). _a_, infested root; _b_, larva; _c_, winged insect; _d-g_, parts of perfect insect enlarged.]

The mouth parts are peculiar in that they are intermediate in form between the sucking beak of Hemiptera and the biting mouth parts of other insects.

[Ill.u.s.tration: FIG. 22.--_Thrips striatus_, with wings enlarged at side.]

Their eggs resemble those of Hemiptera; the larvae and pupae are active, and in form resemble the adult, except in the absence of wings. Some species, also, are wingless in the adult stage.

The pupae are somewhat sluggish and the limbs and wings are enclosed in a thin membrane which is expanded about the feet into bulbous enlargements, giving rise to the name "bladder-footed" (Physopoda) applied to these insects by Burmeister.

"Order DIPTERA ([Greek: dis], twice; [Greek: pteron], wing) or Two-winged Flies. The only order having but two wings, the hind pair replaced by a pair of small, slender filaments clubbed at tip, and called halteres, poisers, or balancers.

[Ill.u.s.tration: FIG. 23.--A Mosquito (_Culex pipiens_). _a_, adult; _b_, head of same enlarged; _e_, portion of antenna of same; _f_, larva; _g_, pupa. (After Westwood.)]

[Ill.u.s.tration: FIG. 24.--A Hawk-fly (_Erax b.a.s.t.a.r.di_). _a_, perfect insect; _b_, pupa; larva shown at side.]

[Ill.u.s.tration: FIG. 25.--A Flesh-fly (_Sarcophaga carnaria_, var.

_saracenae_). _a_, larva; _b_, puparium; _c_, adult insect with enlarged parts.]

"No order surpa.s.ses this in the number of species or in the immense swarms of individuals belonging to the same species which are frequently met with. The wings, which are variously veined, though appearing naked to the unaided eye, are often thickly covered with very minute hairs or hooks. As an order the Diptera are decidedly injurious to man, whether we consider the annoyances to ourselves or our animals of the Mosquito, Buffalo-gnat, Gad-fly, Breeze-fly, Zimb or Stomoxys, or the injury to our crops of the Hessian-fly, Wheat-midge, Cabbage-maggot, Onion-maggot, etc. There are, in fact, but two families, Syrphidae and Tachinidae, which can be looked upon as beneficial to the cultivator, though many act the part of scavengers. No insects, not even the Lepidoptera, furnish such a variety of curious larval characters, and none, perhaps, offer a wider or more interesting field of investigation to the biologist. It is difficult to give any very satisfactory arrangement of these Two-winged flies, though they easily fall into two rather artificial sections.

These are: 1st, NEMOCERA, or those with long antennae, having more than six joints, and palpi having four or five joints. The pupa is naked, as in the Lepidoptera, with the limbs exposed. This kind of pupa is called _obtected_. 2d, BRACHOCERA, or those with short antennae, not having more than three distinct joints, and palpi with one or two joints. The pupa is mostly _coarctate_, _i. e._, is formed within, and more or less completely connected with, the hardened and shrunken skin of the larva.

[Ill.u.s.tration: FIG. 26.--The Sheep Bot (_[OE]strus ovis_). 1, 2, flies; 3, puparium; 4, 5, and 6, larvae or bots.]

"The most anomalous of the Diptera are the Forest-flies and Sheep-ticks (_Hippoboscidae_). They have a h.o.r.n.y and flattened body, and resemble lice in their parasitic habits, living beneath the hair of bats and birds. Their mode of development has always attracted the attention of entomologists. The larvae are hatched in the abdomen of the female, which is capable of distention. There it remains and, after a.s.suming the pupa state, is deposited in the form of a short, white, egg-like object, without trace of articulation, and nearly as large as the abdomen of the female fly. Closely allied to these are the Bat-ticks (_Nycteribidae_), which possess neither wings nor balancers, and remind one strongly of spiders.

"In this order we may also place certain wingless lice (such as _Braula c[oe]ca_, Nitzch), which infests the Honey-bee in Europe, northern Africa, and western Asia, but which has not yet been detected in this country.

[Ill.u.s.tration: FIG. 27.--A Flea (_Pulex_). (From Packard.)]

"Suborder APHANIPTERA ([Greek: aphanes], inconspicuous; [Greek: pteron], wing) or Fleas, comprising the single family Pulicidae, now placed with the Diptera. Everybody is supposed to be familiar with the appearance of the Flea--its bloodthirsty propensities and amazing muscular power; and while everyone may not have the leisure and means to experience the exhilarating influence of the chase after larger animals, there is no one--be he never so humble--who may not indulge in the hunt after this smaller game! In place of wings the flea has four small, scaly plates.

The minute eggs--about a dozen to each female--are laid in obscure places, such as the cracks of a floor, the hair of rugs, etc., and the larva is worm-like and feeds upon whatever animal matter--as grease and blood--or decaying vegetable matter it can find.

"Order ORTHOPTERA ([Greek: orthos], straight; [Greek: pteron], wing), or Straight-winged Insects. Characterized by having the front wings (called _tegmina_) straight and usually narrow, pergameneous or parchment-like, thickly veined, and overlapping at tips when closed; the hind wings large and folding longitudinally like a fan. Transformations incomplete.

[Ill.u.s.tration: FIG. 28.--A Locust (_Acridium americanum_).]

[Ill.u.s.tration: FIG. 29.--A Tree-cricket (_Orocharis saltator_). _a_, female; _b_, male.]

[Ill.u.s.tration: FIG. 30.--The Croton Bug or German c.o.c.kroach (_Phyllodromia germanica_). _a_, first stage; _b_, second stage; _c_, third stage; _d_, fourth stage; _e_, adult; _f_, adult female with egg-case; _g_, egg-case--enlarged; _h_, adult with wings spread--all natural size except _g_.]

"The insects of this order have a lengthened body and very robust jaws, with a correspondingly large head. The legs are strong, and fashioned either for grasping, running, climbing, jumping, or burrowing. As in the other orders, where the transformations are incomplete, the young differ little from the parent, except in the want of wings; and in many instances even this difference does not exist, as there are numerous species which never acquire wings. There are no aquatic Orthoptera. Some are omnivorous, others carnivorous, but most of them herbivorous. They form four distinct sections: 1st, CURSORIA, c.o.c.kroaches; 2d, RAPTATORIA, Mantes; 3d, AMBULATORIA, Walking-sticks; 4th, SALTATORIA, Crickets, Gra.s.shoppers, and Locusts.

[Ill.u.s.tration: FIG. 31.--Hind wing of Earwig. (From Comstock.)]

[Ill.u.s.tration: FIG. 32.--An Earwig. (From Packard.)]

"Suborder DERMAPTERA[2] ([Greek: derma], skin; [Greek: pteron], wing), or Earwigs, consisting of the single family Forficulidae, which may be placed with the Orthoptera. They are rare insects with us, but very common in Europe, where there prevails a superst.i.tion that they get into the ear and cause all sorts of trouble. The front wings are small and leathery; the hind ones have the form of a quadrant, and look like a fan when opened; and the characteristic feature is a pair of forceps-like appendages at the end of the body, best developed in the males. They are nocturnal in habit, hiding during the day in any available recess. The female lays her eggs in the ground, and singularly enough, broods over them and over her young, the latter crowding under her like chicks under a hen."

[2] Euplexoptera of some authors from [Greek: eu], well; [Greek: plecho], folded, referring to the folded wings.

[Ill.u.s.tration: FIG. 33.--A Dragon-fly (_Libellula trimaculata_). (From Packard.)]

"Order NEUROPTERA ([Greek: neuron], nerve; [Greek: pteron], wing), or Nerve-winged insects. Characterized by having the wings reticulate with numerous veins so as to look like net-work. The order forms two natural divisions, the first including all those which undergo a complete, and the second, called Pseudo-neuroptera (Dictyotoptera, Burmeister), those which undergo an incomplete metamorphosis. * * * The insects of this order are, as a whole, more lowly organized, and more generally aquatic, than either of the others. A natural arrangement of them is difficult on account of their degradational character. They present forms which are synthetic and closely approach the other orders, and the evolutionist naturally looks upon them as furnishing an idea of what the archetypal forms of our present insects may have been. They are, as a rule, large and sluggish, with the body parts soft and little specialized, and the muscles weak. Their remains are found in the Devonian and Carboniferous deposits.

"They are mostly carnivorous, and with the exception of the White-ants and certain Book-lice they none of them affect man injuriously, while some are quite beneficial."

[Ill.u.s.tration: FIG. 34.--Caddis-fly, larva and its case. (From Packard.)]

The first division of this order, or the Neuroptera proper, characterized by having incomplete metamorphoses, may be considered under the three following suborders:

"Suborder TRICHOPTERA ([Greek: thrix], hair; [Greek: pteron], wing), or Caddis-flies, containing the single family Phryganeidae, and placed with the Neuroptera, though bearing great affinities with the Lepidoptera.

Every good disciple of Walton and lover of the "gentle art" knows the value of the Caddis-fly, or Water-moth, as bait. These flies very much resemble certain small moths, the scales on the wings of the latter being replaced in the former with simple hairs. The larvae live in the water and inhabit silken cases, which are usually cylindrical and covered with various substances, according to the species, or the material most conveniently obtained by the individual."

Suborder MECOPTERA ([Greek: mekos], length; [Greek: pteron], wing). This suborder includes a peculiar group of insects, the most striking characteristics of which are the mouth-parts, which are prolonged into a rostrum or beak. The wings are long and narrow, and of nearly equal size. The abdomen of the male is constricted near its posterior end and terminates in long clasping organs from which these insects obtain the common name of Scorpion-flies.

[Ill.u.s.tration: FIG. 35.--Panorpa or Scorpion-fly. (From Packard.)]

The larvae of one genus (_Panorpa_) are remarkable for their great resemblance to the larvae of Lepidoptera. They have, however, eight pairs of abdominal legs. The habits of these insects are not well known, but they are supposed to be generally.

Suborder NEUROPTERA. This group as restricted by modern authors is a small one, including the largest species, as in the h.e.l.lgrammite, the Lace-wing Flies, the Ant-lions, and the Mantispas representing the families, Sialidae and Hemerobiidae, with their subfamilies. The first includes the so-called h.e.l.lgrammite Fly (_Corydalus cornutus_), one of our largest and most striking insects, the larvae of which is known as Dobsons by anglers, and is aquatic and carnivorous in habit. The Hemerobiidae is a large family, comprising, as a rule, delicate insects with rather ample gauzy wings. The larvae are predaceous. The common Lace-wing flies are among our most beneficial insects, destroying plant-lice and other soft-bodied species. To the same family belongs the Ant-lion (_Myrmeleon_), the larvae of which have the curious habit of constructing a funnel-shaped burrow in the sand, in the bottom of which they conceal themselves and wait for any soft-bodied insects which may fall into the trap. This family also includes the peculiar Mantis-like insects belonging to the genus _Mantispa_. As in the true Mantis, the prothorax of these insects is greatly elongated and the first pair of legs are fitted for grasping. The larvae are parasitic in the egg-sacs of certain large spiders (genera _Licosa_, _Dolomedes_, etc.), and undergo a remarkable change in form after the first molt. In the first stage the larvae are very agile, with slender bodies and long legs. After molting the body becomes much swollen and the legs are much shortened, as are also the antennae, the head becoming small and the general appearance reminding one of the larva of a bee.

[Ill.u.s.tration: FIG. 36.--Lace-wing fly. _a_, eggs, _b_, larva, _c_, coc.o.o.ns, _d_, fly with left wings removed.]

[Ill.u.s.tration: FIG. 37.--An Ant-lion (_Myrmeleon_). (From Packard.)]

[Ill.u.s.tration: FIG. 38.--Myrmeleon larva.]

[Ill.u.s.tration: FIG. 39.--_Mantispa_ with side view beneath. (From Packard.)]

The second section of the Neuroptera, characterized by complete metamorphosis, comprises the following suborders: