ORDER HEMIPTERA.
Including the Land Bugs, Water Bugs, Plant Bugs, Skaters,
Lantern Flies, Frog Hoppers, Aphides, and their Allies.
The Hempitera are Haustellate insects; they have four wings, which are membranous and naked. Their metamorphosis is incomplete. The order is a very extensive one. The insects, however, are mostly found in the tropical parts of the world, from whence nearly twenty thousand species have been described. In the British Isles their number reaches nearly a thousand.
The study of the Hemiptera has hitherto been sadly neglected, owing to the great majority of them being very small species.
They include the Plant Bugs, Sand Bugs, Water Bugs, Cuckoo Spits, Froghoppers, Plant Lice, and many other familiar forms. The three great divisions into which they are divided are treated by many entomologists as distinct orders. The following will show under each heading the principal distinguishing character of each group or sub-order as we shall designate them.
Sub-Order 1, Heteroptera.—Fore wings of a parchment like consistency.
Sub-Order 2, Homoptera.—Fore wings membranous and naked, similar to the hind ones.
Sub-Order 3, Anaplura.—Wingless; no metamorphosis.
The Heteroptera are regarded as the highest of the three groups, followed by the Homoptera, while the Anoplura constitute a somewhat aberrant series, and are somewhat in the same position as the fleas (Aphaniptera) are to the true Diptera.
TABULAR VIEW
OF THE
PRINCIPAL FAMILIES OF THE HEMIPTERA.
SUB-ORDER I.—HETEROPTERA.
The Heteroptera constitute the first sub-order of the Hemiptera. They include the True Bugs, an extensive group of very varied structure and habits. The greater part of the terrestrial species feed on plants, though some feed on the blood of animals, while the aquatic species are principally carnivorous in their habits. This sub-order is divided into two tribes.
Tribe I.—Geocores or Land Bugs.
This tribe includes the terrestrial species of bugs. It is subdivided into fifteen families.
Family 1, Scutelleridæ.—This extensive family includes the greater portion of the largest and handsomest species of the Land Bugs.
The insects live upon plants, trees, and shrubs, and feed upon the juices, which they suck out of the soft tissues, many of them especially attacking juicy fruits. The family is very well represented in the warmer parts of the world, where also the most beautifully coloured species are met with.
One of the most handsome representatives in Europe is Graphosoma lineatum, which measures nearly half an inch in length. It is reddish in colour and is common on flowers, especially those of the Umbelliferæ, but is not met with in our own country.
Edessa cervus is a native of South America, and another pretty species.
The most familiar British species is what is commonly known as the Colewort Bug (Strachia oleracea), a very pretty insect, which lives on cruciferous plants, and is said sometimes to be injurious in gardens.
Some of the Chinese Bugs belonging to the genus Tesseratoma are the largest species known.
Family 2, Coreidæ.—This family contains a great number of plant-feeding native and exotic species, varying considerably in shape and structure. The majority of European species are, however, of small size in comparison to those found in tropical parts of the world.
The insects of this family are rarely adorned with bright colours, different shades of brown being the prevailing tints, although a few of them are gaily adorned.
In their general habits they much resemble the Shield Bugs.
Two British species are Syromastes marginatus and Verlusia rhombea.
Family 3, Lygæidæ.—The members of this family are, on the whole, much smaller than the Coreidæ, some of the smallest forms of which many of them resemble.
These insects are generally of a red colour, with black bands and spots.
Several species are very injurious to cultivated plants. One of the most destructive of all is Blissus leucopterus, a black insect with white fore wings, each of which is marked with a large black triangular spot on the outer edge. It measures about an eighth of an inch in length. The young larva is red. In the United States this insect, which abounds to a considerable extent, is called the "Chinch Bug."
Family 4, Pyrrhocoridæ.—This family of bugs abounds in all parts of the world, and in Europe and Britain is undoubtedly the most numerously represented of all the families of bugs. A very common species in this country found on nettles is Phytocoris tripustulatus, which is about one-sixth of an inch in length, and generally yellowish in colour.
Family 5, Capsidæ.—This family contains a great number of small species of variegated colours, which feed exclusively on the sap of plants or the juice of fruits.
A rather small species (Capsus ater) is common upon herbage. The male is entirely black; in the female the head and thorax are reddish. The genus Miris and its allies include elongated species, which are found chiefly in grassy places.
Family 6, Tingididæ.—The species of this family differ considerably among themselves in size, structure, and habits; and although the majority of them are carnivorous, others, especially among the smaller species, are herbivorous. One species (Tingis pyri), found in our own country, is sometimes very injurious to pear trees.
Family 7, Cimicidæ.—The type of this family is the common Bed Bug (Acanthia lectularia), which is only too well known to most people. Although treated as a British insect, it does not always appear to have been an inhabitant of these islands, but to have made its way here about the beginning of the sixteenth century. Three other British species have been described as inhabiting the dwelling-places of certain animals and sucking their blood. A. columbaria attacks pigeons. A. hirundinis is found in swallows' nests, and A. pipistrelli feeds on bats.
Family 8, Reduviidæ.—All the insects of this family are predaceous in their habits, and are exceedingly numerous in tropical climates. The largest British species is Reduvius personatus, an insect about three-quarters of an inch long, of a blackish-brown colour with reddish legs. It is well furnished with wings, and flies especially in warm summer evenings, when it frequently enters houses, being attracted by the lights. This insect is said to be a great enemy to the bed bug.
Some of the foreign species of Reduviidæ are most formidable insects, such as the great black Conorrhinus renggeri of Chili, which often attacks travellers when camping out.
Family 9, Emesidæ.—Most of these insects are carnivorous in their habits. The best known species of this family is probably Plæaria vagabunda, a brown, delicately-formed insect, which inhabits trees.
Tribe II.—Hydrocores or Water Bugs.
All the insects belonging to this tribe are either water insects, or found only in the immediate neighbourhood of water. It contains the remaining families of the Heteroptera, six in number.
Family 10, Saldidæ.—The majority of species belonging to this family are small, dull-coloured insects, always found in the neighbourhood, though they are not strictly aquatic.
Family 11, Hydrometridæ.—The habits of most of these insects are herbivorous, and they are all found near water.
Hydrometra stagnorum is a black or brown insect, more or less tinged with reddish, and about half an inch long. It is found running on the surface of water, or else on the banks or among water plants, but is not so active as some of the other species.
Family 12, Gerridæ.—This family includes some very familiar insects, which may be seen running over the surface of every piece of water. These insects, of which several species are abundant in Britain, have boat-shaped bodies. The typical form is Gerris lacustris, which may be met with almost anywhere. They are predaceous in their habits, feeding upon other insects. Some nearly allied, but mostly very small species, with legs even longer in proportion than those of our common forms, are met with at sea within the tropics, and often at a great distance from land.
Family 13, Galgulidæ.—This family only includes a few American species, which are generally brown spotted with yellow. Galgulus oculatus inhabits the southern part of the United States, and measures about two-fifths of an inch in length.
Family 14, Nepidæ.—The species of this family are not very numerous, but are of considerable interest. They are of large size, and very fierce and voracious. The genus Betostoma, found in the East Indies and America, includes the largest species of Heteroptera, some of which measure four and a half inches in length, and nearly six inches in expanse of the wing. Their food consists of small fish, frogs, etc.
The best-known species in our own country is the Water Scorpion (Nepa cinerea), which has the power of inflicting a very painful wound if handled. It measures about an inch in length. In colour it is yellowish-grey, the back of the abdomen being red, and its large front legs, which somewhat resemble the claws of a scorpion, have given rise to the name by which it is popularly known. It is very common in stagnant water.
Family 15, Notonectidæ.—These insects are commonly known as "Water Boatmen," from their habit of rowing themselves about on their backs with their long hind legs. They are carnivorous, feeding on small insects and other "fry."
The most typical British species is Notonecta glauca, a yellowish insect about half an inch long. It is a most predaceous insect, and can bite severely.
Another common species inhabiting our own country is Coriax Geoffroyi, which is nearly half an inch long. The Notonectidæ are all very powerful and active creatures.
SUB-ORDER II.—HOMOPTERA.
This extensive sub-order includes the Cicadas, Lantern Flies, Plant Lice, Scale Insects, etc.
As already pointed out, the most striking general character of this group consists in the uniform texture of the forewings.
There are eleven families included in the Homoptera, all the species belonging to which feed upon vegetable juices.
Family 1, Cicadidæ.—These insects are mostly inhabitants of warm climates, and our only British representative of the family (C. anglica) is one of the smaller species, the wings only expanding about an inch and a quarter. Four or five hundred species, however, are known to inhabit the world, and some of them attain to considerable dimensions.
They generally live upon trees and shrubs, and obtain their nourishment by piercing the tissues and sucking out the juices of their young tender shoots.
The Cicadas are improperly called "Locusts" both in America and Australia, on account of the chirping noise which they perpetually keep up in the woods, both day and night.
Family 2, Fugloridæ.—This family includes the Lantern Flies and Candle Flies, which are remarkable for their large size, bright colours, and strange forms. They are almost all exotic insects.
The largest species is found in South America, and is called the Great Lantern Fly (Fulgora laternaria), measuring nearly three inches in length, and over four inches in expanse of the wings.
The Chinese Lantern Fly (Fulgora candelaria) has a red body, the fore wings being greenish with yellow spots, the hind wings orange colour with black tips.
Cixius nervosus is found in the British Isles, chiefly on alders. It measures about a quarter of an inch in length, and in colour is black with yellow legs, and transparent wings dotted with brown.
Family 3, Membracidæ.—This family is chiefly remarkable for the fantastic shapes assumed by the prothorax.
Most of the species are inhabitants of America, where they occur in wonderful abundance and variety.
A common species, Centrotus cornutus, is found in the British Isles and over the greater part of Europe. It is rather over a quarter of an inch long, black, with a pair of upright horns on the prothorax.
Another common European and British species (Gargara genistæ) is smaller than the preceding, and has no horns on the prothorax.
Family 4, Cercopidæ.—The "Froghoppers" and "Cuckoo-spits" belong to this family. They are chiefly small insects found among grass and bushes in the summer.
A very common species in this country is the common Cuckoo-spit (Aphrophora spumaria), which is about a quarter of an inch in length, and of a yellowish-grey colour. This insect can make a prodigious leap in proportion to its size. It is said to sometimes spring to a distance of two yards. Its yellow larvæ may often be seen on grass and low plants enveloped in a mass of froth, which has given rise to the name of "Cuckoo-spit."
Family 5, Tettigonidæ.—These insects are exceedingly numerous, and are often remarkably elegant in form. They are mostly inhabitants of America, where some three or four hundred species have been described, but in England we have an exceedingly pretty species (Tettigonia viridis), which is common in damp meadows.
Family 6, Ledridæ.—Many of the insects belonging to this family resemble beetles somewhat in appearance. Ledra aurita, which may be considered the type of the family, is a greenish insect, about three-quarters of an inch in length, and found on oak trees.
Family 7, Jassidæ.—This family contains a considerable number of small insects, some of them of great beauty and elegant in appearance. The typical genus is Jassus.
Family 8, Psyllidæ.—This is the first family of the so-called "Plant Lice" or "Blight." They resemble the "Froghoppers" in their habits of jumping. Most of them are small insects, and they subsist on the sap of plants, to which they are sometimes injurious. A few species produce galls.
Livia pyri is a reddish insect, abundant on pear trees. Other common species are found on the alder, ash, oak, and nettle.
Family 9, Aphidæ.—The Aphidæ, or "Plant Lice," "Blight," and "Green Fly," as they are variously called, are amongst the most destructive of insects. They are small and feeble creatures, but make up for their individual insignificance by their immense numbers.
They sometimes exist in countless millions, completely smothering the plants upon which they feed.
Migratory habits seem to be strongly developed among the Aphidæ, hence it is we are so suddenly visited by such enormous quantities of the insects during hot weather in the summer time.
In colour the Aphides are generally green, brown, and black, according to the species. Different kinds live on different plants and trees.
The Hop Aphis (Aphis humuli) lives upon the hop, and its abundance or scarcity is a most important matter to the hop-growers in this country.
One of the most destructive insects of the whole family is the Vine Aphis (Phylloxera vastatrix), which has committed terrible ravages at various times in most of the vine-growing districts on the Continent.
The Aphides have the habit of discharging a sweet sticky substance called honeydew, of which ants are very fond.
The reproduction of the Aphidæ constitutes one of the most interesting chapters in the history of the animal kingdom.
Family 10, Aleyrodidæ.—Many of the insects of this family resemble moths in appearance. Indeed, the typical species, Aleyrodes proletella, a very small reddish insect, was formerly considered to be a moth by the older writers on entomology.
Family 11, Coccidæ.—This family contains the Cochineal Insects, the Scale Insects, and their allies.
The Coccidæ, or Scale Insects, are sometimes very injurious to cultivated plants, but they are also useful, producing cochineal, shellac, manna, and other substances of considerable importance.
The Cochineal Insect (Coccus cacti) is a native of Mexico, and furnishes us with the most valuable and durable red dye that we possess, and the Lac Insect (Coccus lacca), an East Indian insect, produces the well-known lac-dye.
The common Scale Insect (Coccus adonidum) is well known in hothouses and conservatories in our own country, though it is not indigenous, having been imported from abroad.
SUB-ORDER III.—ANOPLURA.
This sub-order contains only one family, which is considered to be the last and lowest group of the Hemiptera, of which it may be regarded as a very degenerate form. The insects have no wings, and live upon the blood of other animals.
Family 1, Pediculidæ.—The "Lice" are a very extensive family, but at present not very well known. Almost every mammal has a louse peculiar to itself.
Three species infest man. The Head Louse (Pediculus capitis), found on the head, especially in children. The Body Louse (Pediculus vestimenti), found in the clothes; and the Crab Louse (Phthirius inquinalis), a broader and shorter insect, found in the hair on the face and body of uncleanly persons.
The lice infesting different races of men differ in colour—thus, those found on niggers are black; and those on Europeans are whitish.
Other species of lice infest the dog, cat, pig, mouse, elephant, monkey, etc.
The Pediculidæ undergo no metamorphoses.