Diptera 



251 



eyes, and the neck is so slender and flexible that it 

 can be turned almost through a complete circle. The 

 feelers vary greatly in form in the different groups. 

 The mandibles and blades of the first maxills, if pre- 

 sent, are piercing stylets, and the epipharynx is often 

 modified for the same purpose ; the hoods of the second 

 (or first ?) maxillae form a sucker. The fore-body 



Fig. 140. — d. Horn-fly (Hamatohia serrata, Rob.-Desv.), Europe ; b. larva ; 

 c. pupariuin, magnified 8 times ; a. egg, magnified 20 times. From Riley, 

 Insect Life, vol. 2 (U.S. Dept. Agr.). 



segments are fused into a firm capsule, the prothorax 

 being greatly reduced and largely concealed above by 

 the mesothorax ; the mesoscutum and mesocutellum 

 form most of its upper aspect. The legs are usually 

 slender and often spiny, the feet with five segments 



