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. 108.Syrphu8 rlbesilA.. Larva. B. Pupa. C. Imago. (" Regne Animal. 11 ) 



The ordinary Diptera^ which possess one pair of functional 

 wings attached to the mesothorax, resemble the Hemiptera 



FIG. 109. Eristalis floreus. d, front of the head: e. labrum; /, mandible ; g, maxilla 

 and palpus ; z, labimn ; /*. extremity of the labium separately and more macrni- 

 fled; **e, inner surface of the parag!osae ; ***?'. the ro\vs of hairs on the inner 

 surface ; Z, the ligula ; m, the cardo and submentum. (After Newport.) 



in possessing a usually fleshy proboscis, often tumid at its 

 extremity, which is formed by the confluent second maxillae. 



