60 THE BUTTERFLY VIVARIUM. 



those of Grasshoppers, and their tribe generally, 

 require a month. Those of Clisiocampa Neustria, 

 and many other Moths, whose eggs are laid in the 

 autumn, are not hatched in less than nine months, 

 while a spring brood of the same insect probably 

 comes forth in as many days. This is the case with 

 Butterflies' eggs also, the first brood being hatched 

 in a few weeks, the second remaining in the egg 

 during the winter. 



Having described the leading features of our 

 present knowledge respecting the insect egg till the 

 period of hatching, we must now see how the 

 embryo Caterpillar escapes from his miniature 

 prison. 



The mode of exit of the larva from the egg-shell 

 is very different in different kinds. In general the 

 little larva gnaws his way out at the part nearest 

 the head, much as a chicken at the proper time pecks 

 at the shell of its prison till it forces an exit. 

 This gnawing process often costs the embryo Cater- 

 pillar some hours of labour, especially when the shell 

 is thick, as in the case of the Clisiocampa Neus- 

 tria. Some shells, however, are furnished with a 

 regularly hinged lid, which the larva has only to lift 

 in order to effect his escape. In some cases the lid 

 is lifted by a very complicated spring and balance 



