368 



THE ANATOMY OF INVERTEBRATED ANIMALS. 



mals, birds,- and bees, a circular wall, or short proboscis, in- 

 vests the other parts of the mouth. There are, first, two 

 lateral, protrusible, horny plates ; secondly, an anterior and a 

 posterior seta ; the latter stronger, and grooved longitudinally 

 in front. Between these is a single fine seta. Gerstfeldt 

 considers that the last answers to the hypopharynx ; the 

 second pair, to the labrum and the second maxillae ; the first 

 pair, to the first maxillae ; and that there are no mandibles. 



Fig. I(i8.—Syrphns ribesii.—k. Larva. B. Pupa. C. Imago. (" Regne Animal.") 



The ordinary Z>//>^era, which possess one pair of functional 

 wings attached to the mesothorax, resemble the Hemiptera 



Fig. Wi.—Erutalis jlorem.—d, front of the head; e. labrum; /, mandible ; q, maxilla 

 and palpus ; «, labium ; z*. extremity of the labium separately and more magni- 

 fied ; **i, inner surface of the para?lo«sae ; ***e. the rows of 'liairs on the inner 

 surface ; I, the ligula ; m, the cardo and submeiitum. (After Newport.) 



in possessing a usually fleshy proboscis, often tumid at its 

 extremity, which is formed by the confluent second maxillae. 



