PROC. ENT. SOC. WASH., VOL. 22, NO. I, JAN., 1920 19 



1916, C. T. Greene; Dead Run, Va., June 20 to 30, im:>, R. C. 

 Shannon; June 23, Banks; Cabin John, Md., June 29, 191(5, 

 F. R. Cole; July S and October, 1910, R. M. Fouts; Chain Bridge, 

 Va., June 23, 1915, Banks, C. T. Greene; Falls Church, Va., 

 June 20, Banks; July 2, 1912, July 3, 19 Hi, C. T. Greene; Belts- 

 ville, Md., July 1, 1917, McAtee. 



D. brevis Banks. Plummers Island, Md., June 18, 191(5, C. 

 T. Greene. 



Cyrtopogon Loew. 



C. lutatius Walker. Dead Run, Va., May 24, 1910, R. C. 

 Shannon; Beltsville, Md., May 13 and 24, 1917, McAtee. The 

 latter collections were made about piles of cordwood. 



Lasiopogon Loew. 

 Key to the Species. 

 A. Legs reddish brown; abdomen black, pruinose on hind angles and narrow 



hind margins of segments. Length 5-7 mm terricola. 



AA. Legs black; abdomen broadly prninose across posterior portions of seg- 

 ments. Length about 9 mm tetragrammus. 



L. terricola Johnson. Common in its favorite situations, bare 

 sandy areas, often along paths on roads; April 17 to July 10; in 

 copula May 2. P. I. 



L. tetragrammus Loew. Less common and more local than 

 last. Great Falls, Va., April 30, May 12, 20, Banks; May 2, 

 C. T. Greene; Virginia near Plummers Island, May 7, 1916, 

 H. L. Viereck; May 21, 1910, McAtee; Plummers Island, Md., 

 May 1, 1915, May 5, 1914, May 7, 191(5, R. C. Shannon; Mary- 

 land near Plummers Id., May 10, 1910, McAtee; Glencarlyn, 

 Va., May 21, 1917, C. T. Greene. 



Holcocephala Jaennicke. 



Key to the Species. 



A. Abdomen broad at base, usually reddish yellow, at least in fresh spec- 

 imens. abdomi nulls. 



A A. Abdomen more slender and elongate, narrowed toward base, brownish, 



pruinose on hind margins of segments 1 to 3 .cuh'ii. 



H. abdominalis Say. Undoubtedly the most numerous in in- 

 dividuals of any of our species of Asilidae; usually seen perched 

 on tips of grass blades in damp situations. Season June 20 to 

 October 3. Among prey of this species are the ants; Solenopsis 

 molesta and Lasius sp. P. I. 



H. calva Loew. Far less numerous than last. Great Falls, 

 Va., July 13, Banks; August 11, 1915; Scott's Run, Va., July 25, 

 1915, McAtee; Dead Run, Va., July 2S, 1915, R. C. Shannon; 

 Plummers Island, Md., July I, 1907, A. K. Fisher, McAhc : 

 July 11, 1909, McAtee; Maryland near Plummers Island, June 

 29, '30, July 13, 1913, R. C.' Shannon; Cabin John, Md., July 



