80 INTERNAL ANATOMY OF INSECTS. 
reversed cone. This pouch the grub can close when- 
ever it pleases, so as to cover its spiracles \ And nu- 
merous other larvae, both of Diptci'a and Coleoptcra 
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. t. xxix./. 2. c, s. 
