212 STATES OF INSECTS. 



vse act as if they foresaw the assumption of a state in 

 which they will be deprived of legs. It is the suspension 

 of the forthcoming pupa that is the object in view ; and 

 though this can be hung by the tail in the same way with 

 those of the first class, yet it is plain that it cannot be re- 

 tained in a horizontal position, which for some unknown 

 reason is essential to it, without some support to its an- 

 terior extremity. It is necessary for the larva, therefore, 

 not only to fix its posterior legs amongst a collection of 

 silken fibres, but to spin a girth of the same material 

 round its body. This girth, though apparently of a sin- 

 gle thread, will be found on examination to be composed 

 of several, often as many as fifty or sixty ; and is fastened 

 on each side of the body of the larva about the middle, 

 to the surface under which it is placed. Three different 

 modes of fixing these girths are adopted by the caterpil- 

 lars of different butterflies. Some, as those of the com- 

 mon cabbage-butterfly (Pieris Brassier), which have re- 

 markably pliable bodies, bend them almost double on 

 one side, then fix the thread and carry it over to the 

 other in the same position, repeating this operation as 

 often as is necessary. Others, as that of Lyccena Argus 

 and many more of the Papiliones Rurales and JJrbico- 

 Ice L., which have a short and more rigid body, after 

 having bent the head on one side so as to fix one end of 

 the thread, bring themselves into a straight position, and, 

 by a manoeuvre not easily described, contrive to intro- 

 duce the head under the thread, which they then bend 

 themselves to fasten on the other side, pushing it to its 

 proper situation by the successive tension and contrac- 

 tion of their segments. But the most curious mode, 

 though indeed that which seems most natural, is adopted 



