56 HISTORY OF 



so frequently undergo. But the intestines take 

 up but a small part of the animal's body, if com- 

 pared to the fatty substance in which they are in- 

 volved. This substance changes its colour when 

 the insect's metamorphosis begins to approach ; 

 and from white it is usually seen to become yellow. 

 If to these parts we add the caterpillar's imple- 

 ments for spinning (for all caterpillars spin at one 

 time or another), we shall have a rude sketch of 

 this animal's conformation : however, we shall re- 

 serve the description of those parts, till we come 

 to the history of the silk-worm, where the manner 

 in which these insects spin their webs will most 

 properly find place. 



The life of a caterpillar seems one continued 

 succession of changes ; and it is seen to throw off 

 one skin only to assume another ; which also is 

 divested in its turn : and thus for eight or ten 

 times successively. We must not, however, con- 

 found this changing of the skin with the great 

 metamorphosis which it is afterwards to undergo. 

 The throwing off one skin and assuming another, 

 seems, in comparison, but a slight operation among 

 these animals ; this is but the work of a day, the 

 other is the great adventure of their lives. In- 

 deed, this faculty of changing the skin is not pe- 

 culiar to caterpillars only, but is common to all 

 the insect kind, and even to some animals that 

 claim a higher rank in nature. We have already 

 seen the lobster and the crab outgrowing their 

 first shells, and then bursting from their confine- 

 ment, in order to assume a covering more roomy 

 and convenient. It is probable that the louse, 



