TABANIM. I77 



ginal and five posterior cells always present; basal cells 

 large, anal cell usually closed, but never far before the 

 border of the wing; the marginal vein encompasses the 

 entire wing. Squamae of considerable size. Flies of mod- 

 erate or large size, never slender; rarely with brilliant 

 colors. 



Fig. 64. Pangonia guttata; enlarged. 



This family includes the insects commonlyealled horse- 

 flies, green-headed flies, etc., and has a wide distribution 

 over the world. About eighteen hundred species have 

 received names, of which not less than two hundred and 

 seventy-five are from North America. None of the spe- 

 cies are active on dark, cloudy days, though some are 

 partial to shady woods, and are very annoying to stock 

 in such places. On clear, warm days, horseflies begin 

 flying as soon as the sun has warmed the air, and are 

 iS 



