Hemiptera

“ Several families of bugs are predaceous in habit, attacking other insects—often members of their own order—and sucking their juices. Others are scavengers feeding on decaying organic matter; the pond skaters, for example, live mostly on the juices of dead floating insects. And some, like the bed-bugs, are parasites of vertebrate animals, on whose bodies they live temporarily or permanently, and whose blood they suck.
The Hemiptera are especially interesting as an order from the variety of aquatic insects included therein. ”

“ Elytra, when present, consisting of three divisions. Tarsi three-jointed.—This is one of the largest and most important families of Hemiptera. Upwards of 2000 species are already known; the habits seem to be chiefly of a predaceous nature, the creatures drawing their nutriment from the animal rather than from the vegetable kingdom, and their chief prey being in all probability other kinds of Insects. There is, perhaps, no family of Insects exhibiting a greater variety of form and colour. ”

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

“ The orthoptera include, as familiar examples, cockroaches, crickets, katydids, and grasshoppers; the neuroptera white ants, May-flies, caddis-flies, dragon-flies or devil’s darning needles, and hoodlbugs; the hymenoptera common ants, wasps and bees; the lepidoptera butterflies, moths, silk-worms, and humming-birds; the hemiptera plant lice, cochineals, and locusts; the diptera mosquitoes, house-flies, horse-flies, and bot-flies.
The order hemiptera is frequently divided into two, according as the wings are of a uniform texture, homoptera, or of a varied texture, heteroptera ”

“ As far as Lepidoptera are concerned, and certain of Hemiptera, they are right—the antennæ in these creatures are the seat of the organs of audition. But in Orthoptera, in most of Coleoptera, Hymenoptera, and Diptera, and in certain bugs (Hemiptera) , they are located elsewhere. The habit that almost all insects have of retracting their antennæ when alarmed by noise, or otherwise, has done much to advance and strengthen the opinion that these appendages are the seat of insect ears ”

“ Classification.—The number of described species of Hemiptera must now be nearly 20,000. The order is divided into two sub-orders, the Heteroptera and the Homoptera. The Anoplura or lice should not be included among the Hemiptera, but it has been thought convenient to refer briefly to them at the close of this article.
Heteroptera
In this sub-order are included the various families of bugs and their aquatic relations. The front of the head is not in contact with the haunches of the fore-legs. There is usually a marked difference between the wings of the two pairs. ”

“ The Gyrodactylus elegans, of which we have spoken above, contains embryos similarly enclosed, and if these facts had been known at an early period, the celebrated theory of the enclosure of germs, so warmly advocated by Bonnet, would have preserved still longer its intrepid defenders.
With but few exceptions, all the Hemiptera are parasites of the vegetable kingdom. There are only very few which attack animals. ”

“ The hemiptera, which live on the sap of vegetables, are parasites in the same manner as those which live at the expense of animals. We ought not to make a difference between the manner of life of the bugs of plants and those of animals. ”

“ Before leaving this subject, I may remark that just as in plants some glands secrete honey that attracts insects, others a resinous liquid that repels them, so the secretions of different genera of the homopterous division of the Hemiptera are curiously modified for strikingly different useful purposes. We have seen that by many species of plant-lice, scale-insects, and leaf-hoppers, a honey-like fluid is secreted that attracts ants to attend upon them. ”

“ The Hemiptera are without exception sucking Insects, and {533}the mouth-organs of the individual are of one form throughout its life. In this latter fact, coupled with another, that the young are not definitely different in form from the adult, Bugs differ widely from all other Insects with sucking-mouth. They agree with the Orthoptera in the facts that the mouth does not change its structure during the individual life, and that the development of the individual is gradual, its form, as a rule, changing but little. ”

“ Development.—In most Hemiptera the young insect (fig. 3) resembles its parents except for the absence of wings, and is active through all stages of its growth. In all Hemiptera the wing-rudiments develop externally on the nymphal cuticle, but in some families—the cicads for example—the young insect (fig. 10) is a larva differing markedly in form from its parent, and adapted for a different mode of life, while the nymph before the final moult is sluggish and inactive. In the male Coccidae (Scale-insects) the nymph (fig. 4) remains passive and takes no food. ”

“ It may be added that the mental faculties of the Diptera are probably higher than in most other insects, in accordance with their highly-developed nervous system. [21]
Order, Hemiptera (Field-Bugs) .—Mr. J. W. Douglas, who has particularly attended to the British species, has kindly given me an account of their sexual differences. The males of some species are furnished with wings, whilst the females are wingless; the sexes differ in the form of their bodies, elytra, antennæ and tarsi ”

“ Those that gain an entrance into the skin should be cut out, care being taken to remove the insect entire.
BEDBUGS
In the order Hemiptera, or the true "bugs" in an entomological sense, we find a few forms that may carry disease. The bedbug (Fig. 35) (Cimex lectularis) has been accused of transmitting plague, relapsing fever and other diseases. Very recent investigations show that the common bedbug of India (Cimex rotundatus) harbors the parasite that causes the disease known as kala azar, and there is no doubt that it transmits the disease. ”

“ This is the rule (see Chapters II and III) with the Apterygota, the Orthoptera, and most of the Hemiptera. In the last-named order, however, we find in certain families marked divergence between larva and imago, for example in the cicads, whose larvae live underground, while in the coccids, whose males are highly specialised and females degraded, there succeeds to the larva—very like the young stage in allied families—a resting instar, which in the case of the male, suggests comparison with the pupa of a moth or beetle. ”

“ No specialist who works long at any large group of animal forms, especially at insects, can escape meeting with these problems. This is particularly discovered when, in monographing a family, species are found resembling insects belonging to another order. Thus, in recently working out some Hemiptera for the 'Biologia Centrali-Americana,' I found in the family Lygæidæ a species with all the superficial form and colour of an Earwig (Forficula) belonging to the order Orthoptera ”

“ Even the ants, except in a few tropical districts, rarely act upon the offensive. The Hemiptera contain one semi-parasitic species which has attained a "world-wide circulation," and one degraded, purely parasitic group. But the Diptera, among which the fleas are now generally included as a degenerated type, comprise more forms personally annoying to man than all the remaining insect orders put together. These hostile species are, further, incalculably numerous, and occur in every part of the globe. ”

“ Hemimetabolous: manifesting an incomplete metamorphosis, but with a marked difference between the stages: specifically the Ephemerida, Odonata and Perlidae. {Scanner's comment: nowadays applied to far more orders, generally to those that undergo a marked metamorphosis, but without a pupal stage.}
Hemiptera: half-winged: an ordinal term applied to insects in which the mouth parts consist of four lancets inclosed in a jointed beak or rostrum; metamorphosis incomplete: the primaries may be of uniform texture throughout (Homoptera) or may be thickened at base, membranous at tip (Heteroptera) . ”

“ The alar organs in Hemiptera exhibit a very frequent form of variation within the limits of the same species; this has not yet been elucidated. [474] In some cases in the Heteroptera nearly all the individuals of a generation may have the wings aborted; sometimes this occurs as a local variation. In Aphidae the occurrence of winged and wingless individuals is very common, and has even become an important factor in their extraordinary life cycles. (See Chermes, etc., subsequently.)
Internal anatomy.—The alimentary canal presents considerable diversity and some remarkable features. ”

“ He considers that these ancient fossils may be classified with the existing Orders of Insects, though they cannot be placed in existing families; and he assigns the palaeozoic fossil Insects at present known, to the Orders Neuroptera and Orthoptera, and to the homopterous division of Hemiptera. The greater part of the species he looks on as Neuroptera, and places in six families—Megasecopterides, Protephemerides, Platypterides, Stenodictyopterides, Protodonates, and Protoperlides. ”

“ His classification was founded mainly on the nature of the wings, and five of his orders—the Hymenoptera (bees, ants, wasps, &c.) , Coleoptera (beetles) , Diptera (two-winged flies) , Lepidoptera (moths and butterflies) , and Hemiptera (bugs, cicads, &c.) —are recognized to-day with nearly the same limits as he laid down. His order of wingless insects (Aptera) included Crustacea, spiders, centipedes and other creatures that now form classes of the Arthropoda distinct from the Hexapoda ”

“ The value of the generic characters afforded by the modifications which the figure of the cells undergoes, may be inferred from the fact stated by M. Jurine, that he could, in most cases, determine the genus of a hymenopterous insect from the inspection of the wings alone.
As among the Hemiptera, the inferior wings are more or less closely united to the superior when in action, but this is effected by a different kind of mechanism. ”

“ These observations demonstrate that in several genera of insects, belonging to the Hemiptera, sex is predetermined at least as early as the fertilized egg, and may be traced to antecedent conditions that preexist in the germ-cells before their union. In most of the species the spermatozoa are predetermined as male-producing and female-producing forms, equal in number, that differ visibly in the constitution of the nuclei. ”

“ The Reduviidæ, or assassin-bugs are capable of inflicting very painful wounds, as most collectors of Hemiptera know to their sorrow. Some species are frequently to be found in houses and outhouses and Dr. Howard suggests that many of the stories of painful spider bites relate to the attack of these forms. ”

“ No hemiptera are known to be poisonous, that is, to have a poison-gland connected with the sting, like that of the bee, and careful dissections by the eminent French naturalist, Lacaze-Duthiers, of three European species of Cicada, have not revealed any poison apparatus at the base of the sting. Another proof that it does not pour poison into the wound made by the ovipositor is, that the twig thus pierced and wounded does not swell, as in the case of plants wounded by Gall flies, which, perhaps, secrete an irritating poison, giving rise to tumors of various shapes. ”

“ The occasional development of wings is probably of service to the species in enabling the insects to reach new fresh-water breeding-grounds. This family of Hemiptera (the Hydrometridae) and the Saldidae contain several insects that are marine, haunting the tidal margin. One genus of Hydrometridae (Halobates) is even oceanic in its habit, the species being met with skimming over the surface of the sea hundreds of miles from land. Probably they dive when the surface becomes ruffled. In these marine genera the abdomen often undergoes excessive reduction (fig. 5) . ”

“ There are a number of Hexapoda, or true insects, which are, in one way or another, poisonous to man. These belong primarily to the orders Hemiptera, or true bugs; Lepidoptera, or butterflies and moths (larval forms) ; Diptera, or flies; Coleoptera, or beetles; and Hymenoptera, or ants, bees, and wasps. There are various ways in which they may be poisonous. ”

“ Some of the Hemiptera, for example, the lice and bed-bugs, are predaceous, sucking the blood of other animals.
Fig. 64.—A water-strider, Hygrotrechus
sp. (From Jenkins and Kellogg.)
The water-striders (fig. 64) catch other insects, both those that live in the water and those which fall on to its surface, and holding the prey with their seizing fore legs they pierce its body with their sharp beak and suck its blood. They lay their eggs in the spring glued fast to water-plants. The young water-striders are shorter and stouter in shape than the adults. ”

“ Vestigial palps have been described in various species of Hemiptera, but the true nature of these structures is doubtful. In front of the rostrum and the piercers lies the pointed flexible labrum and within its base a small hypopharynx (fig. 2, IV. d) consisting of paired conical processes which lie dorsal to the “syringe” of the salivary glands. This latter organ injects a secretion into the plant or 259 animal tissue from which the insect is sucking. The point of the rostrum is pressed against the surface to be pierced ”

“ The circumstance that there are still numerous wingless species among the Orthoptera, and that some of these (Blattidæ) are so like certain Crustacea (Isopods) in habit that both are indicated by the same name (“Baratta”) by the people in this country, can scarcely be regarded as of any importance.
The contrary supposition that the oldest Insects possessed a “complete metamorphosis,” and that the “incomplete metamorphosis” of the Orthoptera and Hemiptera is only of later origin, is met by serious difficulties. ”