Microscopical Essays. 



21CJ 



{ The pupa * of this infeft weighs, a little after it's change, 

 much heavier than it does in it's beetle Mate ; this is alfo the cafe 

 with the pupa of the bee and hornet. The latter has been 

 found to weigh ten times as much as the hornet itfelf ; this is 

 probably occafioned by a fuperabundant degree of moifture, by 

 which thefe infecls are kept in a hate of inactivity (a kind of pre- 

 ternatural dropfy) till it is in fome meafurc diffipated; in pro- 

 portion as this moifture is evaporated, the {kin hardens and dries'; 

 fome days are required to fweat off this fuperfluous moif ure. 

 If the (kin is taken off at this time, many curious circumilances 

 may be noted ; but what claims our attention moft is, that the 

 horn, which is fb hard in the male beetle when in a ftate of ma- 

 turity, that it will bear to be fharpened againft a grindftone, f in 

 the pupa ftate is quite foft, and more like a fluid than a folid 

 fubftance. 



How long the fcene of mutation continues is not known ; 

 fome remain during the whole winter, more particularly thofe 

 who quit the larva ftate in autumn, when a fudden cold 

 checks their further operations, and confequently they remain 

 without any food for feveral months. Some fpecies of the 

 beetle tribe go through all the ftages of their exiftence in a feafon, 

 while others employ near four years in the procefs, and live as 

 winged infecls a year. 



When the proper time for the final change arrives, all the 

 mufcular parts grow iirong, and are thus more able to fhake oft 



D d 2 their 



* Swamrr.e 'dam's Bock of Nctu.e, p. 144* 

 f Mouftet, p. 152. 



