367 



Family Tetanoceridse — The Marsh Flies 



Head short, as broad or broader than the thorax; face retreating, 

 more or less perpendicular below; oral vibrissa absent. Abdomen com- 

 posed of six segments, rather long and narrow, snb-cylindrical. Wings 

 longer than the abdomen; auxiliary vein entire, wholly separated from 

 the first vein; posterior basal and anal cells complete, small. Legs of 

 moderate length, the femora with bristles, the middle pair with a short 

 bristle near the middle of the anterior surface; tibige with preapical 

 bristle. 



The adults are found in moist places, along the banks of streams, 

 ponds, etc. and most of them may be recognized on sight by the shape 

 of tlie head. 



Tetanocerida' I. — 1, 2, 3, Sepedon, wing, hind leg and head; 4, Dictya sp. ; 5, Tetanocera; 

 6, Dyctia nana; 7, Djctia; !<, Thccomjia ( S. America) ; 9, Trigonometopus (Sapromyzidae) 

 (Williston). 



