HALF-WINGED INSECTS. 291 



takes place. Sometimes the animal 

 is not able to effect its exit, and dies 

 in the struggle. These shells may 

 often be found clinging to trees and 

 fences in considerable numbers. It 

 is supposed that the Seventeen-years 

 Locusts really remain in their grub 

 state under ground seventeen years, 

 but Jaeger holds to the contrary. 



494. The Frog-hoppers are so call- 

 ed from their great power of leaping. 

 Fig. 225.-Grub of cicada. Thoge o f t ^ s f am iiy most familiar to 



us are the Tree-hoppers, of which a specimen is given in 

 Fig. 226. The thorax or chest of these insects 

 is very large. They are commonly motionless 

 for hours together ; but if they are disturbed, 

 they make a sudden leap of two or three hund- 

 Fi g . 226.-The red times their own length, and, spreading out 

 their wings, fly off to some other spot. The 

 insects of this family are sometimes called Froth-hoppers, 

 from a frothy fluid which exudes from them. In some 

 species, in tropical countries, this exudation is very abun- 

 dant. 



495. The Aphidse, or Plant Lice, have small, round, 

 full bodies, presenting different colors on different plants. 

 Some have wings and some have not. They live in 

 great numbers on the stalks and leaves of plants, sucking 

 the sap with their beaks. The postures which they 

 sometimes assume is very amusing. I saw the past 

 summer in my garden some stalks of the wild Aster 

 lined with them from top to bottom, and every one had 

 its head downward. The hind legs did not touch the 

 stalk at all, but were raised up, and the insects rested 

 on the fore legs and the beak. Thus standing out, and 

 being of a reddish color, they gave the appearance of or- 

 namental appendages, until the eye was brought near 

 enough to see what they were. 



