22 PROC. ENT. soc. WASH., VOL. 22, NO. 2, FEB., 1920 



AA. Veins at outer ends of discal and fourth posterior cells forming a dis- 

 tinct angle. 



C. Three sub marginal cells present Pogonosoma. 



CC. Only two submarginal cells. 



D. First posterior cell narrowed or closed; nearly bare species, with 



pruinose markings on thorax Nusa. 



DD. First posterior cell rather widely open; slightly to very hairy 



species. 

 K. Body nearly bare, hind femora with spinigerous tubercles 



beneath Lampria. 



EE. Body usually more hairy, hind femora without spinigerous 



tubercles. 

 F. Pile sparse to dense; that on abdomen in part crisped ap- 



pressed ; abdomen usually parallel-sided Laphria. 



FF. Pile dense over most of body, erect, usually black and 



bright yellow; abdomen broadest behind middle 



Dasyllis. 



Cerotainia Schiner. 



C. macrocera Say. Common; June 5 to August 22; known to 

 come to light. P. I. 



Atomosia Macquart. 

 Key to the Species. 



A. Femora black, except for narrow pale rings at base and apex. . . .pnella. 

 AA. Femora more extensively pale. 



B . Femora reddish brown, broad bands on anterior pairs, and outer sur- 

 faces of posterior pair, black glabrata. 



BB. Femora pale yellow; with never more than minute spots of black at 



bases of hind ones sayii. 



A. puella Wiedemann. Very common; extreme dates of col- 

 lection, May 31 and September 5. Almost always found on bark 

 of trees, on poles or other upright wood surfaces. Has been 

 found feeding on Simulium. P. I. 



A. glabrata Say. Apparently rare; Falls Church, Va., August 

 10, 11 and 19, Banks; rests on leaves near the ground. 



A. sayii Johnson. Common, June 10 to September 5; habits 

 like last; Chironomus has been noted among the prey. P. I. 



Pogonosoma Rondani. 



P. melanoptera Wiedemann. Great Falls, Va., July 12, 1916, 

 J. N. Knull; August 1, 1916, McAtee; Cabin John, 'Md., June 

 4, 1916, R. C. Shannon; Washington, D. C., June 27, Banks; 

 Falls Church, Va., June 12, 1916, July 3, 1915, reared, C. T. 

 Greene; June 29, July 3, 1916, J. N. Knull; Beltsville, Md., July 

 4, July 30, 1916, W. R. Walton. 



