VADE MECUM. 1;) 



tlic skull, jttWM, and nil tlie exterior parts, l)otti scaly and 

 niembranaceous, which compose its ujjper and under lij) ; its 

 untentue, palfii, and even those crnstaceous pieces within the 

 liea»l, which serve as a fixed hasis to a number of muscles, 

 with the spiracles, the claws, and sheaths of the anterior legs, 

 and iu Koneral the traces of all that is visible in the external 

 figure of the Caterpillar. This change is effected by the 

 insect withdrawing itself from the outer skin, when it finds 

 itself incommoded from being confined within too narrow a 

 compass ; but to accomplish this change, is a painfiil pro- 

 cess, and the work of some labour and time ; it generally 

 fasts a whole day after moulting. The Caterjiillars of Lepi- 

 dopterons insects, with the few exceptions before mentioned, 

 are destitute of all means of defence, and ore the prey of 

 birds and other voracious creatures. Many of them feed 

 close to the ground, or under the surface, subsisting on the 

 lower i)arts or roots of jihuits ; and for tliis reason are .seldom 

 seen, and remain unknown. Many also are of the colour 

 of the i)lant on which they feed, and hence they are with 

 ditliculty discovered by their enemies. A large proportion of 

 them are green of difl'crent .shades, sometimes beautifully 

 contrasted with black bands ; a circumstance which renders 

 the CaterjiilUir of one of our finest insects Papilio Muc/iaoii, 

 of tills order, us lovely as the lly. No general judgment, 

 however, can be formed of the beauty of the future fly, from 

 the colour of the larvce; for it often haiipens that the .splen- 

 did Caterpillar gives a jilain Butterfly, and vice-versa. A 

 Caterpillar in its adult state, is the uio.st ravenous of all 

 animals ; it will eat double its own weight of leaves in 

 one day. These voracious habits, with its slow crawling 

 motion, render these insects, notwithstanding the beauty and 

 variety of their colouring, not the mo.st agreeable objects of 

 human curiosity. There are, however, many Naturalist'" 



