sist of several silken threads. The second day 

 of labour they give to the cocoon the form which 

 they intend it to take, multiplying the threads 

 and shutting themselves up, and by the third 

 day they are entirely hidden. The day follow* 

 ing the caterpillar continues to work in the inte- 

 rior, always with the same thread of silk which 

 it never breaks, and when it has given to its lodg- 

 ing all the perfection that it is susceptible of, it 

 becomes changed into a chrysalis. It has been 

 calculated that the single thread of silk which 

 forms a cocoon, is more than three miles in length. 



In this, the second period of its existence, the 

 insect is no longer a worm, but a creature, the 

 limbs of ^lich are all enclosed in one or more 

 enveloping folds, and bent down on its breast^ 

 possessing no power of motion. The caterpillar 

 had taken care, in finishing his cocoon, to make 

 one of its ends less solid than the other, and to 

 moisten the silk with a liquid which corrodes it, ; v 

 and thus at the end of fifteen or sixteen days 

 after the change of a caterpillar into a chrysalis, 

 the newly developed moth or insect has only to 

 make a slight effort in order to effect its passage 

 through a cocoon, the tissue of which is in other 

 parts so close that it is almost impossible to tear 

 it. 



In the third period of its existence the insect 

 attains all the organic perfection which belongs ^ , 

 to the rank in creation that it is destined to fill. 

 The bands of the nymph, chrysalis or aurelia, 

 are broken, and the insect commences a new 



