LEPIDOPTEEA. 149 



which elongates it ; thus the split soon extends from the end or 

 the commencement of the first ring as far as the other side of the 

 end of the fourth. The upper portion of the body which corre- 

 sponds to these four rings is then laid bare, and the caterpillar 

 has an opening sufficiently large to serve it as an egress 

 through which it can entirely leave its old skin. It curves its 

 fore part, and draws it backwards ; by this movement it dis- 

 engages its head from under its old envelope, and brings it up to 

 the beginning of the crack ; immediately upon this it raises it, 

 and causes it to go out through this crack. The moment after- 

 wards it stretches out its fore part and lowers its head. There 

 now remains for the caterpillar nothing but to draw its hinder part 

 from the old case." 



This excessively laborious operation is finished in less than a 

 minute. The new livery which the caterpillar has just put on is 

 fresh and bright in colour. But the animal is exhausted by 

 its fast, and the efforts which it has made. It requires a few 

 hours in which to regain its equilibrium, and at the same time 

 its former activity and voracity. 



THE CHRYSALIS, OB PUPA. 



Having attained its full development, the caterpillar ceases to 

 eat, as at the approach of a moult it empties its intestinal canal 

 by copious ejections ; it loses its colours, and becomes dull 

 and livid, and thus prepares itself to enter a new phase of its 

 existence. 



Some, when about to transform themselves into chrysalides, sus- 

 pend themselves to foreign bodies. Others spin a cocoon com- 

 posed of silk and other substances, which secures them against the 

 attacks of their enemies and the action of the atmosphere. Those 

 which suspend themselves can be divided under two heads, accord- 

 ing to the mode of their suspension : 1. Those which suspend 

 themselves perpendicularly by the tail. 2. Those which, after 

 having fixed themselves by the same part, suspend themselves 

 horizontally, by means of a silk thread passed round the 

 body. 



To understand the difiiculty which the first of these operations 



