Bugs, Cicadas, Aphids, and Scale-insects 
166 
Fore wings with basal half thickened and parchment-like, apical half thin 
and membranous; the four wings lying flat on the back when folded, 
the membranous tips overlapping; sucking-beak arising from the 
front part of head, and the head usually separated from the pro¬ 
thorax by a more or less distinct neck. Heteroptera. 
Of these three suborders the Parasita, or sucking-lice, are degenerate 
wingless species and will be considered last. The Heteroptera include 
the so-called “true bugs” with fore wings thickened at base, and when 
folded lying flat on the back, as the squash-bug, chinch-bugs, and the great 
majority of the species in the order, while the Homoptera include the cicadas, 
the tree- and leaf-hoppers, the aphids or plant-lice, the mealy-winged flies, 
and the degenerate scale-insects. 
SUBORDER HOMOPTERA. 
Key to Families of the Homoptera (includes both Nymphs and Adults). 
(Adapted from Woodworth.) 
Proboscis seeming to rise from the middle of the sternum, or proboscis wanting; insects 
less than ^ inch long. 
Hind femora much larger than other femora.(Jumping plant-lice.) Psyllid^e. 
Hind femora not much larger than the others. 
Legs long and slender...(Plant-lice.) Aphidiid^e. - 
Legs short, or wanting. 
Feet of one joint, or wanting.(Scale-insects.) Coccid^e. 
Feet of two joints.(Mealy wings.) Aleyrodid,e. 
Proboscis plainly arising from the head. 
With three ocelli, sometimes (nymphs) with large front tibiae and no wings. 
(Cicadas.) Cicadid^e. 
With two ocelli or none, and the front tibiae not enlarged. 
Antennae inserted on head below the eyes.(Lantern-flies.) Fulgorid^e. 
Antennae inserted in front of and between the eyes. 
Prothorax extending back over the abdomen-(Tree-hoppers.) Membracid^e. 
Prothorax not extending back over the abdomen. 
Hind tibiae with few spines.(Spittle-insects.) Cercopid^e. 
Hind tibae with two rows of spines.(Leaf-hoppers.) Jassid.e. 
Perhaps no other insect-species has any single characteristic of its life- 
history of the same interest as the extraordinarily long duration of the adoles¬ 
cence of the seventeen-year cicada. That a single one of the 300,000 and 
more known species of insects should have a period of development from 
egg to adult of more than sixteen years, while this period in all other insects 
varies from a few days to not more than three years—comparatively few 
insects live, all told, more than a year—is perhaps the most striking excep¬ 
tional fact in all insect biology. The other members of the family 
Cicadidae, to which this insect belongs, have, as far as known, an immature 
