172 THE CATERPILLAR KIND. 



have acquired the necessary force and solidity, the butterfly then 

 seeks to disembarrass itself of those bands which kept it so long 

 in confinement. Some insects continue under the form of an 

 aurelia not above ten days, some twenty, some several months, 

 and even for a year together. 



The butterfly, however, does not continue so long under the 

 form of an aurelia as one would be apt to imagine. In general, 

 those caterpillars that provide themselves with cones, continue 

 within them but a few days after the cone is completely finished. 

 Some, however, remain buried in this artificial covering for 

 eight or nine months, without taking the smallest sustenance 

 during the whole time ; and though in the caterpillar state no 

 animals were so voracious, when thus transformed they appear 

 a miracle of abstinence. In all, sooner or later, the butterfly 

 bursts from its prison, not only that natural prison which is 

 formed by the skin of the aurelia, but also from that artificial 

 one of silk, or any other substance in which it has inclosed 

 itself. 



The efforts which the butterfly makes to get free from its 

 aurelia state, are by no means so violent as those which the in- 

 sect had in changing from the caterpillar into the aurelia. The 

 quantity of moisture surrounding the butterfly is by no means 

 so great as that attending its former change ; and the shell of 

 the aurelia is so dry, that it may be cracked between the fingers. 



If the animal be shut up within a cone, the butterfly always 

 gets rid of the natural internal skin of the aurelia, before it eats 

 its way through the external covering which its own industry 

 has formed round it. In order to observe the manner in which 

 it thus gets rid of the aurelia covering, we must cut open the 

 cone, and then we shall have an opportunity of discovering the 

 insect's efforts to emancipate itself from its natural shell. When 

 this operation begins, there seems to be a violent agitation in 

 the humours contained within the little animal's body. Its fluid 

 seems driven, by a hasty fermentation, through all the vessels, 

 while it labours violently w T ith its legs, and makes several other 

 violent struggles to get free. As all these motions concur with 

 the growth of the insect's wings and body, it is impossible that 

 the brittle skin which covers it should longer resist ; it at length 

 gives way, by bursting into four distinct and regular pieces. 

 The skin of the head and legs first separates ; then the skin at 

 the back flies open, and dividing into two regular portions, dis- 

 engages the back and wings ; then there likewise happens an- 

 other rupture in that portion which covered the rings of the 

 pack of the aurelia. After this, the butterfly, as if fatigued with 

 it« struggles, remains very quiet for some time, with its wings 

 pointed downwards, and its legs fixed in the skin which it had 



