DIPTERA 



307 



The larvas are aquatic or semi-aquatic. As far as known, they are 

 predacious, feeding on various small animals, some upon snails, others 

 upon the larva? of insects. 



Family Stratiomyid^e ,. 



The Soldier-flies 



The soldier-flies are so called on account of the bright-colored 

 stripes with which some of the species are marked. In the 

 more typical members of this family the abdomen is broad and myta - 

 greatly flattened (Fig. 535), and the wings when at rest lie parallel 

 upon each other over the abdomen (Fig. 536). 



The antennas vary greatly in form, in some genera the flagellum is 

 long and consists of several quite distinct segments (Fig. 537), in others 

 it is short with but few indistinctly separated seg- 

 ments and with an arista (Fig. 538). 



The larvas are spindle-form or elliptical and flat- 

 tened. Some are aquatic, some live in cow-manure 

 and some under the loosened bark of trees. 



There are three small families of flies, the Xylo- 

 myidce, Xylophagidce , and Ccenomyidce which occur in 

 the series here and which the student will find dis- 

 cussed in detail in "An Introduction to Entomology" 

 Fig. 537. b y J- H. Comstock pp., 832, 833, and 834. fig. 538. 



Sc /?! /?;+: 



Fig. 536. — Wing of Stratiomyia. 



Family Rhagionid^ 



The Snipe-flies 



These trim-appearing flies have rather long 

 legs, a cone-shaped abdomen tapering towards the 

 hind end (Fig. 539) and sometimes a downward- 

 projecting proboscis, which with the form of the 

 body and legs has suggested the name snipe-flies. 

 The body is naked or hairy, but it is not clothed 

 with strong bristles. Frequently the hairy cover- 

 ing, though short, is very dense and is of strongly- tenna' of Chryso- 

 contrasting colors. Three ocelli are present. The antennas are pila - 

 only three-jointed and the third segment bears a style or an arista (Fig. 540). 



Fig. 539- — 

 Chrysopila tho- 

 racica. 



