ESCAPE FROM THE OLD SKIN. 147 



spun for this purpose, it turns and twists its body 

 in various directions, and alternately swells and 

 contracts its different segments. The object of 

 these motions and contortions seems to be, to se- 

 parate the exterior skin, now become dry and 

 rigid, from the new one just below it. After con- 

 tinuing these operations for some hours, resting 

 at intervals, without motion, as if exhausted by 

 their violence, the critical moment arrives : the 

 skin splits in the back, in consequence of the still 

 more violent swelling of the second and third 

 segments. The opening thus made is speedily 

 increased by a succession of swellings and contrac- 

 tions of the remaining segments ; even the head 

 itself often divides into three triangular 

 pieces, and the enclosed larva by degrees 

 withdraws itself wholly from its old skin." 

 The engraving is intended to show the 

 larva just escaping out of its old skin. 



Sometimes the larva comes out of its 

 skin at the side ; sometimes it has been 

 seen to bite off portions of the skin. 

 The most common way is that above 

 described. The skin, when cast in this man- 

 ner, resembles a sort of universal coat, which 



