FOREST LIFE. 



219 



not be used. This species is not quite so large as 

 the dog-day-harvest fly, and is black and brick-red in 

 color. It is remarkable on account of the slowness 

 of its growth, the nymphs requiring seventeen years 

 for their development in the North and thirteen years 

 in the South. As all of the members of one genera- 

 tion reach the adult state at about the same time, the 

 species appears in immense swarms which attract 

 general attention. In many localities several broods 

 coexist ; this explains the fact that in such places 

 these insects appear several times during a single 

 period of seventeen or thirteen years. The adult 

 female lays her egg in slits which she makes in the 

 twigs of trees. The eggs hatch in about six weeks. 

 The young nymphs drop to the ground and bury 

 themselves in the earth, where they live by sucking 

 the juices from the roots of trees. When full-grown, 

 seventeen or thirteen years later, they crawl up to 

 the surface of the ground and undergo their last 

 molt on the trunks of trees. The last nymph skin is 

 left clinging to the bark where the transformation 

 occurred, and soon afterward the songs of the insects 

 are heard. 



The student should collect nymph skins, adults, 

 and twigs in which the eggs have been laid. 



The cicadas constitute the family CICADID/E (Ci- 

 cad'i-dae) of the order Hemiptera. 



THE TREE-HOPPERS, OR BROWXIE-BUGS. 



The tree-hoppers are so called because they live 

 upon trees, bushes, and vines, and can jump with 

 great agility. Many of them are grotesque in ap- 

 pearance, having great humps on their backs; and in 

 15 



