CH. IV.] HISTORY OF THE SILKWORM. 79 



dissimilar to that with which it was previously in- 

 vested. 



We will proceed to trace the changes which it 

 undergoes, commencing with the egg, which is 

 about the size of a grain, and of a yellow colour 

 when fresh ; but after a few days, becomes rather 

 dark, of a bluish cast. The period which the egg 

 requires is dependant on the temperature of the 

 climate ; so much so, that some eggs may be pre- 

 served during the winter and spring ; or they may 

 be quickened by artificial means, when the natural 

 food appears in sufficient quantity for their sup- 

 port. 



When hatched, it appears as a black worm, about 

 a quarter of an inch in length, gradually becomes 

 larger and whiter, and in about eight days its head 

 enlarges and it is attacked by illness, which lasts 

 for three days ; refusing food, and remaining in a 

 state of lethargy. This illness is supposed to be on 

 account of the smallness of the skin. The worm 

 appears at the end of the third day much wasted, 

 and throwing off a kind of humour, which has ex- 

 uded between its body and the skin about to be 

 cast off, at the same time emits from its body silken 

 cords, so as to fasten the abandoned skin to a spot 

 while the insect forsakes it, which it performs in 

 the following manner. It first rubs its head among 

 the leafy fibres, so as to disencumber itself of the 

 scaly covering, and then breaks through that part 

 of the skin nearest the head. This action causes 

 the larva very great exertion. Soon afterward it 

 disengages its fore feet, and then the body is quickly 

 drawn from the skin, which remains stationary. 

 This operation occupies two or three minutes. The 

 insect then begins to feed with renewed vigour and 

 health. The skin sometimes refuses to separate 

 from the body ; in which case the pressure occa- 

 sions swelling and inflammations, and generally 

 terminates in death. 



