THE LABVA 



23 



growth, might easily be led to suppose that the poor creature was 

 displaying the earlier symptoms of a serious and perhaps fatal 

 illness. 



But soon an encouraging symptom is observed. The caterpillar 

 begins to get restless. Its front segments are turned alternately 

 right and left, and are also made to swell out much beyond their 

 normal size. Then in a \ery short time — often less than a minute 

 from the first appearances of restlessness — the skin, which has 

 become somewhat dry and brittle, splits along the back over the 

 second, third and fourth segments, revealing a new and bright coat 

 beneath. The caterpillar continues its struggles and, in addition 

 to the previous movements, causes the swelling to move backward 

 along the body. This, acting like a 

 wedge, causes the rent in the old coat 

 to extend in that direction. 



The caterpillar now draws its head 

 backward, and, with a few convulsive 

 struggles, pulls the front segments 

 out of their old skin, and passes its 

 head out of the rent in the back. 

 With its foremost segments thus 

 rendered perfectly free, it walks 

 straight out of the old garment, 

 which is left still fixed by the legs to 

 the silken carpet. 



The larva, although now fresh and smart in its appearance, is 

 exhausted by these struggles and its prolonged fast. The new skin, 

 moreover, is very soft and tender, even to the cases of the head 

 and legs, which are normally very hard. But a short period of 

 rest suffices to dry its skin and sharpen its appetite, and then it 

 eats more vigorously than ever. 



^Ye will now leave the caterpillar for a moment while we look 

 at its cast-off clothes. They are still clinging to a stem so firmly 

 that they can scarcely be removed without injury. The hard shell 

 that covered the head and jaws is perfect in form, and so are the 

 claws and cases of the legs. All the hairs or spines that happened 

 to adorn the previous owner still retain their positions ; and the 

 whole skin, although always more or less shrivelled, is sometimes 

 so sHghtly altered in form that it might be mistaken for a living 

 caterpillar if not closely examined. 



But this is not all. For, according to the accounts of some 



Fig. 15, — Tiik Caterpillar of 

 THE Dakic Green rRiTiL- 

 LARY Butterfly. 



