150 THE LIFE OF AN INSECT. 



upright, and assume precisely the same appearance 

 as those on the former skin. 



The keeper of silk-worms can tell us well, and 

 perhaps with many a sigh, that the period of 

 moulting is one of great peril to his tender 

 charge. The Iarva3 are sick and feeble for some 

 time after each period of moulting ; and large 

 numbers die at this time, apparently unable to 

 bear the exhaustion attending the loss of their old 

 skin. Larvae generally are much debilitated by 

 each moult that takes place ; for a variable period, 

 sometimes for some hours, sometimes for a whole 

 day, they will refuse food, and lie without motion. 

 All their parts are very soft and tender, and re- 

 quire hardening by exposure to the air. After a 

 certain period, however, these effects pass off; the 

 larva recovers its original strength, its body becomes 

 firm, its colour brightens, and appears more bril- 

 liant than ever ; and, above all, like convalescents 

 among ourselves, its appetite is twice as keen as 

 before, which, when we call to mind what has 

 been already said about the voracity of larva?, it 

 will be confessed, appears scarcely possible. 



These changes of skin take place a definite 

 number of times in the larva? of each species. The 



