1 66 Bugs, Cicadas, Aphids, and Scale-insects 



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 J inch long. 



Hind femora much larger than other femora (Jumping plant-lice.) PSYLLID^:. 



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. 



Antennas 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 



