Bugs, Cicadas, Aphids, and Scale-insects 169 



in the east. It is gregarious and is attended by ants which feed on a sweetish 

 substance excreted by it. It lays its eggs in little white waxen frothy masses. 

 A curiously humpbacked form is Senilia camelas (Fig. 240). The best known 



and most injurious tree-hoppers are those 

 of t^ genus Cerasa, of which the species 

 C. buhalus, or buffalo tree-hopper (see initial 

 letter of this chapter), injures fruit-trees 

 both by piercing and sucking sap from 



,nw3 



Fig. 238. 



Fig. 239. 



Fig. 240. 

 (After Lugger; natural 



Fig. 238. — The black-backed tree-hopper, Arlhasia galleala 



length 5 inch.) 



Fig. 239. — .\ tree-hopper, Enchenopa gracilis. (Three times natural size.) 

 Fig. 240. — .\ tree-hopper, Senilia camelas. (Three times natural size.) 



them, and by making slits in the twigs to lay eggs in. It is about \ inch 

 long, light grass-green with whitish dots and a pale yellowish streak on 

 each side. On the front there are two small sharp processes jutting out one 

 on each side from the prothorax, and suggesting a pair of horns, hence 

 the name. It is common on apple and many other trees from the middle 

 of summer until late in the autumn. The eggs are laid in pairs of nearly 

 parallel and slightly curved slits. The young hatch in the spring following 

 egg-laying. 



Walking over our lawns or through pastures and meadows we often 

 startle from the grass hundreds of small, usually greenish, little insects that 

 leap or fly for a short distance, but soon settle again in the herbage. Nearly 

 all these sm;dl and active in.sects are sap-sucking leaf-hoppers, of the family 

 Jassida:, one of the largest and most injurious of the Hemipterous families. 

 It is stated by careful students of these grass-pests that from nearly one- 

 fourth to one-half of all the grass springing up annually is destroyed by 

 leaf-hoppers. Professor Osborn estimates that over one milUon leaf-hoppers 

 can and often do live on an acre of grass-covered ground. These insects 

 are rarely more than \ inch long, and most of them are nearer half of that. 

 The body is more slender than in the tree-hoppers, and is usually widest 

 across the prothorax or a httle behind it, tapering back to the tip of the 

 folded wings. The head is more or less triangular, as seen from above, 

 and the face is oblique, sloping back to the base of the fore legs. The 

 family is a large one, containing many species, of which several are well 



