Hatching — Growth loi 



young insect is three times as wide as deep, having 

 already assumed the flattened form of body which 

 adapts cockroaches to life in concealed situations. In 

 some Grasshoppers the vestigial limbs on the first 

 abdominal segment are not lost until hatching-time. 

 In Earwigs, some Beetles, Lacewing flies and Fleas, 

 one or more sharp points or cutting-edges, " hatching- 

 spines," are developed on the head of the embryo ; 

 by means of these the egg-shell is pierced. After 

 leaving the egg-shell, the embryo has to cast off the 

 amnion before hatching is complete. This process 

 has been observed in an American locust, which, by 

 inflating the loose skin between its head and thorax, 

 bursts the amnion, and then slips it over the head, 

 withdrawing first the feelers and legs, then the hind- 

 body, and finally the hind feet. Kicking away the 

 now discarded membrane with these, the newly- 

 hatched locust walks away (66). 



In the vast majority of insects the development of 

 the egg takes place for the most part, after it has 

 been laid by the mother. In some cases, however, the 

 egg is hatched within the body of the parent, and the 

 young insect is born in an active state. The Plant- 

 lice furnish the most familiar example of this " vivi- 

 parous " reproduction, which also occurs in some May- 

 flies, two-winged Flies and a few Beetles. 



Young Insects and their Growth. — In the more 

 primitive insects, the newly-hatched young is a minia- 

 ture reproduction of its parent. A young Springtail 

 or Cockroach (see fig. I d) is at once recognised as 

 such, though the wings of the latter are not fully 

 developed until the final moult, as is the case with 

 all winged insects. The newly-hatched Grasshopper 

 or Locust (fig. 63 a) has no wings, but it shows from 

 its earliest days the long leaping hind-legs of its 

 parent. In the course of growth, repeated moults, or 



