THE CATERPILLAR. 65 



by warmth, or increasing vigour, the parts 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 cater- 

 pillar state no animals were so voracious, when 

 thus transformed they appear a miracle of ab- 

 stinence. In all, sooner or later, the butterfly 

 bursts from its prison, not only that natural pri- 

 son 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 enclosed itself. 



The efforts which the butterfly makes to get 

 free from its aurelia state, are by no means so 

 violent as those which the insect had in changing 

 from the caterpillar into the aurelia. The quan- 

 tity 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 



VOL. VI. E 



