132 



ENTOMOLOGY, 



with an apical style or a thick dorsal bristle; parasitic in the ab- 

 domen of wasps and bees. Conops tibialis Say. 

 Family Syrphidae. A spurious longitudinal vein between the third 



Fig. 156. a Fig. 157. 



FIG. 156. Bot-fly of the ox. a, larva. FIG. 157. Horse bot-worm, enlarged. 



and fourth longitudinal veins; first posterior cell closed; no depres- 

 sion in the face for the antennse. Often wasp- or bee-like in shape 



Fig. 159. Fig. 160. 



FIG. 158. Rat-tailed pupa-case of Eristalis. 

 FIG. 159. Merodon posticata. a, its pupa-case. 

 FIG. 160. Si/rphus (Mesogr&fta.) politus, and Aphis-maggot, natural size. 



and coloration (Williston). The larvae of many species devour 

 Aphides, etc., and may be observed among their colonies. The 

 larva of Eristalis, which lives in stagnant, brackish, or excremen- 

 titious water, breathes by a long caudal filament. 



Sub-order 3. Orthorhapha. In this group the pupa is 

 usually free, not coarctate, and escapes from the larval skin 



