BUTTERFLIES 73 



the eggs of the Danaidae, and it is possible that 

 these are distasteful to their foes at all stages of 

 their existence. The eggs of butterflies are always 

 laid in safe places and as near as possible to the 

 proper food for the young ; the butterfly never sees 

 her young and can have no clear idea as to the 

 respective merits of cabbages, carrots, and oak- 

 leaves, yet she makes no mistake. 



The larva, or caterpillar, is soft and fleshy and is 

 very easily injured. It is furnished with a biting 

 mouth, soft fleshy fore-legs, and a terminal sucker. 

 It has three pairs of harder jointed legs correspond- 

 ing to the legs of a butterfly and which are 

 sometimes very long, as in the lobster moth. The 

 great and only work of caterpillars is to eat, and 

 this they do all night, many of them all day as well. 

 They feed on the leaves of plants by means of their 

 powerful jaws, and have no need even to stop to 

 take breath, for their breathing is carried on by 

 means of spiracles or pores along the sides of the 

 body which lead to the tracheal tubes by which the 

 respiration of insects is effected. Their rapid 

 growth soon renders their skin too tight and the 

 outer layer, or cuticle, is thrown off like that of a 

 crab or lobster ; after this they eat more ravenously 

 than ever to make up for lost time, often commenc- 

 ing with their cast-off clothes. As a rule there are 

 several of these castings before the caterpillar 

 attains its full size. Their gain in weight is 

 prodigious, the caterpillar of one of the hawk moths 

 for instance, Acherontia, weighing about one-eighth 

 of a grain on leaving the egg, in thirty days 



