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



Fore wings with basal half thickened and parchmcnt-likc, 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). 

 (.■\dapted 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-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.«. 



Feet of two joints (Mealy wings.) Aleyrodid*. 



Proboscis plainly arising from the head. 



With three ocelli, sometimes (nymphs) with large front tibia; and no wings. 



(Cicadas.) C1CADID.E. 

 With two ocelli or nunc, and the front tibiae not enlarged. 



.\ntenna: inserted on head below the eyes (Lantern-flies.) Fulcorid.*;. 



Antennae inserted in front of and between the eyes. 



Prothorax extending back over the abdomen (Tree-hoppers ) Membracid*. 



Prothorax not extending back over the abdomen. 



Hind tibis with few spines (Spittle-insects.) Cercopid^. 



Hind tibx with two rows of spines (Leaf-hoppers.) Jassid.*. 



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 30o,ocx) and 

 more known species of insects should have a period of develojjment 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 

 Cicadidas, to which this insect belongs, have, as far as known, an immature 



