INSECTA 



93 



used up and 'the young grasshopper is ready to hatch (G). 

 Soon after fertilization the female grasshopper drills a 

 hole in the ground with her abdomen and deposits thirty 

 or forty eggs, which remain covered until spring. Most of 

 the development within the egg-shell therefore takes place 

 after the eggs are laid. In spring, when the ground is 

 warm enough, the egg-shells break and little wingless 

 nymphs work their way to the surface. The young grass- 

 hoppers begin to feed at once, but cannot grow on account 

 of their hard exoskeletons. This difficulty is overcome by 

 a periodical casting of the outer skin (Fig. 45). After such 

 a moult a grasshopper is soft for a short time and grows 



D 



FIG. 45. A grasshopper nymph shedding its skin. (After Packard.) In E the 

 adult which emerged is drying its wings; in F, it is ready to fly away. 



very rapidly. Then the exoskeleton hardens again and 

 there can be no more growth until the next moult. After 

 the first moult a tiny pair of wings appear. These increase 

 in size each time the skin is shed, but do not become func- 

 tional until the last moult, when complete maturity is 

 attained. After becoming mature the grasshopper seeks a 

 mate, starts off a new generation, and dies. Thus the 

 cycle goes round. The grasshopper must strain every 

 faculty to keep up its race. Its arduous struggle has but 

 one end to produce offspring and die. 



But is this all? The characteristics of animals are 

 handed down with great fidelity generation after genera- 

 tion. Heredity is jealous of any change. But as the ages 



