58 HISTORY OF 



sometimes lifts up its head, and then lets it fall 

 again ; it sometimes waves it three or four times 

 from side to side, and then remains in quiet. At 

 length some of the rings of its body, particularly 

 the first and the second, are seen to swell consi- 

 derably, the old skin distends and bursts, till, by 

 repeated swellings and contractions in every ring, 

 the animal disengages itself, and creeps from its 

 inconvenient covering. 



How laborious soever this operation may be, it 

 is performed in the space of a minute ; and the 

 animal having thrown off its old skin, seems to 

 enjoy new vigour, as well as acquired colouring 

 and beauty. Sometimes it happens that it takes 

 a new appearance, and colours very different from 

 the old. Those that are hairy still preserve their 

 covering, although their ancient skin seems not to 

 have lost a single hair ; every hair appears to 

 have been drawn, like a sword from the scabbard. 

 However, the fact is, that a new crop of hair 

 grows between the old skin and the new, and 

 probably helps to throw off the external covering. 



The caterpillar having in this manner conti- 

 nued for several days feeding, and at intervals 

 casting its skin, begins at last to prepare for its 

 change into an aurelia. It is most probable, that 

 from the beginning all the parts of the butterfly 

 lay hid in this insect in its reptile state ; but it 

 required time to bring them to perfection, and a 

 large quantity of food to enable the animal to un- 

 dergo all the changes requisite for throwing off 

 these skins, which seemed to clog the butterfly 

 form. However, when the caterpillar has fed 



