28 CLASS INSECTA. 



membranous Avings, and folded like a fan ; two mobile, 

 crustaceous bodies, formed like small elytra, situated at the 

 extremity of the thorax,* and for organs of mastication, 

 simple jaws, in the form of bristles, with two palpi. 



The twelfth order, the Diptera, has six feet ; two mem- 

 branous and extended wings, accompanied in almost all of 

 them, by two mobile bodies, formed like balancers, situated 

 behind them ; and for organs of manducation, a sucker, 

 composed of a variable number of bristles or hairs, enclosed 

 in an inarticulated sheath, most frequently formed like a 

 proboscis, and terminated by two lips. 



* Formed, as we would presume, by pieces analogous to the epaulette 

 ' pterygodes of the lepidoptera. 



