ORDER DIPTERA : THE NEMATOCERA, ETC. 49 



expanded and very finely serrated at tip ; (4) a similar pair 

 of maxillae which are more coarsely serrated at tip. In the 

 males of Culicidae (Fig. 1 1 ) mandibles and maxillae are wanting, 

 and often also the hypopharynx is hard to trace as an inde- 

 pendent structure, the proboscis appearing to consist solely 

 of epipharynx and labium, which resemble the same parts of 

 the female ; the males do not suck blood, but live on juices. 



The thorax is covered with scales or hairs, the form and 

 distribution of these being subject to some diversity. In a 

 dorsal view the predominant segment is the mesothorax, or, 

 rather, its dorsal elements, the scutum and scutellum. The 



. label! a 

 Fin. 11.— Head of male A%<yplitUs. 



pronotum, or dorsal element of the prothorax, shows only as 

 a narrow collar or a pair of shoulder-lobes. The metanotum 

 is overlapped by the scutellum, and as a rule is quite bare. 

 The scutellum itself is narrow ; its free edge is commonly tri- 

 lobed, but sometimes is simply arched. There is no " trans- 

 verse suture " to the scutum. 



The abdomen, which is long and narrow, consists of 9 

 segments, the last one of which is bilobed. In the female the 

 two terminal lobes are simple, but in the male they have a 

 complicated structure, and carry a pair of slender, chitinous, 

 clasping-hooks. The surface of the abdomen is either scaly 

 or hairy. 



The wings (Fig. 7) are long and narrow, and are com- 

 pletely encompassed by the costal vein ; their front edge (the 



