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Suborder Homoptera

A curious and important assemblage of insects belong to the Homoptera. Those creatures which we know as leaf-hoppers, tree-hoppers, cicadas, plant-lice, flea-lice, bark-lice, scale insects, mealy bugs, and white flies all belong here. Their name is legion and they are without exception, destructive to plant life. Their mouth-parts are formed for sucking, and their transformations are incomplete. Their forewings are not modified, as with the Heteroptera, or true bugs, but are more normal and are usually held roof-like over the back when at rest. The front of the head is always bent under so that it touches the base of the front legs. Beyond these points, their structure is very diverse, and beyond the fact that all are plant feeders their habits are also very diverse. In their life histories some of them, particularly the plant-lice, the bark-lice and the periodical cicada (or so-called seventeen-year locust), present some of the most interesting, and, in fact, some of the most astonishing, phenomena in the whole field of biology. The progressive degradation, after birth, of the female of the scale insects, from an active, highly animated creature to a blind, legless, protoplasmic globule, and the contrasting development of the male of the same species, from a minute, crawling mite to a virile, winged, active and highly organized creature whose head is practically all eyes, is one of the most extraordinary life histories among all insects, while the alternate forward and backward development which occurs in the genus Margarodes in this family is even more strange. Then, too, the remarkably adapted parthenogenetic life of the plant-lice, with their alternation of food plants and their relations with ants, make their study one of fascinating interest.

The Homoptera is a large group of insects. No one knows how large. The plant-lice and the scale insects of Europe and North America have been rather well studied, largely on account of the economic interest which attaches to them. Yet, even from North America, many new species are being found, even in these groups, each year. The tree-hoppers and the leaf-hoppers and some of the other groups, however, are very poorly known, and, in fact, the whole suborder, as it is represented in tropical regions, is but slightly known. Collectors in out-of-the-way places have neglected this group, and doubtless very many thousands of species will yet be discovered and described. A small group of American workers, including Messrs. Osborn, Van Duzee, Baker, Gillette and Ball, are doing admirable work upon the leaf-hoppers and tree-hoppers, but there is still room for many more investigators of these interesting insects. They are easily preserved and make an interesting collection. The study of the scale insects may safely be left to the small army of economic workers who have taken up their study during the past ten years, but the plant-lice need many more students. The difficulty of properly preserving the insects of this group, since they must be kept in alcohol or formalin or mounted upon microscope slides, doubtless deters many from entering upon their study. But the life histories of very few of our North American species are known, and many important and most interesting facts are still to be learned about a host of species.

Table of Families

Beak plainly inserted in the head; feet with three segments; antennae minute, bristle-like.

Beak apparently inserted between the forelegs; feet with one or two segments; antennae usually prominent, but sometimes wanting.

1--Ocelli three in number; the males with musical organs . . . . . Family Cicadidae

Only two ocelli or none; males not musical.

2--Antennae inserted in front of and between the eyes.

Antennae inserted on the sides of the cheeks beneath the eyes . . . . . Family Fulgoridae

3--Prothorax not prolonged above the abdomen.

Prothorax prolonged into a horn or point above abdomen . . . . . Family Membracidae

4--Hind shanks with one or two stout teeth below and at tip with a crown of short, stout spines . . . . . Family Cercopidae

Hind shanks with a row of spines below . . . . . Family Jassidae

Feet usually with two segments; wings when present four in number.

5--Wings transparent.

Wings opaque, whitish . . . . . Family Aleyrodidae

Feet with only one segment; males without mouth-parts and with two wings only; females wingless and scale-like or gall-like in form, and covered with wax in plates, layers or in powdery form . . . . . Family Coccidae

6--Hind thighs swollen; antennae with nine or ten segments . . . . . Family Psyllidae

Legs long and slender; antennae with three to seven segments . . . . . Family Aphididae