CHAPTER IX 



Order Diptera (continued) : The Aschiza 



In the flies of this division (Fig. 47) the frontal lunule is 

 often indistinct and the frontal suture is not present at all. 

 The antennae are usually composed of 3 simple segments and 

 an arista which is generally dorsal, rarely terminal. The 3rd 

 longitudinal vein is not forked, and there are never more 

 than three posterior cells in the wing. The empodia are 

 not pulvilliform. 



.fronTalhnuh 



Fio. 47.— Head of a Syrpliid Fly. 



Four families are here included ; not one of the species 

 sucks blood, and few of them are of any importance from the 

 medical standpoint. 



Family SYRPHlD^iE, Hover-flies. Many of the species of 

 this very large family are bright coloured, some of them 

 resemble wasps and bees, and a few look like blue-bottles 

 or green-bottles. They live on nectar and pollen, and are 

 generally seen poised over or settled on flowers. The 

 antennae consist of 3 segments, usually with a dorsal arista. 

 Between the 3rd and 4th longitudinal veins, more or less 

 parallel with them, and crossing the anterior cross-vein, a 



14i 



