PROCEEDINGS OF THE 



ENTOMOLOGICAL SOCIETY OF WASHINGTON 



VOL. 22 FEBRUARY, 1920 No. 2 



DISTRICT OF COLUMBIA DDPTERA: ASILIDAE. 



BY W. L. McATEE AND NATHAN BANKS. 



(Continued from page 20.) 



Taracticus Loew. 



T. octopunctatus Say. Fairly common; May 30 to August 4. 

 P. I. 



Nicocles Jaennicke. 



Key to the Species. 



A. Apical half of wing dusky, with a clear spot confined to marginal cell; 



antennal style half as long as third segment politus. 



AA. Dark coloring of wings in the form of clouds along veins, the cells more 

 or less hyaline; antennal style only one-fourth as long as third seg- 

 ment pictus. 



N. pictus Loew. Great Falls, Va., April 15, 30, May 12, 

 Banks; April 20, 1916, on flowers of Benzoin aestivale, McAtee; 

 March 26, April 2, 1917, C. T. Greene; Maryland near Plummers 

 Island, May 10, 1916, McAtee; Cabin John, Md., April 11, 1915, 

 R. C. Shannon; April 11, 1917, R. M. Fouts; High Island, Md., 

 May 12, 1898, R. P. Currie; Falls Church, Va., April 5, Banks; 

 Beltsville, Md., March 25, 1917, W. R. Walton. Dead twigs 

 are a favorite perch for this species. The following prey has been 

 identified: the ant, Lasius sp. and the dung beetle, Aphodius 

 femoralis. 



N. politus Say. Hyattsville, Md., August 14, 1912, Septem- 

 ber 17, 1910, F. Knab; October 11, Banks; Bladensburg, Septem- 

 ber 23, 1915, October 2, 1914, in copula, R. C. Shannon. Pygos- 

 tolus ar genii fer Loew, described from District of Columbia ma- 

 terial is a synonym. 



Laphriinae. 



Key to the Genera. 



A. Veins at outer ends of discal and fourth posterior cells forming nearly a 

 straight line. 



B. First antennal joint much more than twice as long as^second 



Cerota inia . 



BB. First antennal joint not more than twice as long as second . .Atomosia. 



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