80 INTERNAL ANATOMY OF INSECTS. 



reversed cone. This pouch the grub can close when- 

 ever it pleases, so as to cover its spiracles a . And nu- 

 merous other larvae, both of Diptera and Coleoptera 

 that devour unclean and oily food, have doubtless some 

 protection of this kind for their spiracles and respira- 

 tory plates. 



I am, &c. 



a Reaum. iv. 428. /. xxix./. 2. c, s. 



