PROC. ENT. SOC. WASH., VOL. 22, NO. 2, FEB., 1920 25 



FF. Segments 1-3 of abdomen with no more than scant fringes 

 of yellow hair posticatus. 



D. affinis Macquart. Plentiful in its season which is the 

 autumn; earliest date, August 10, latest, November 4; mostly 

 seen on tree trunks and telephone poles; in copula, September 

 30. Food species identified are : Oxyporus lateralis and Diabrotica 

 12-punctata. An attempt has been made to identify Laphria 

 melanopogen Wiedemann (Ausz. zweifl. Ins. I, 1828, pp. 520-521, 

 [Kentucky]) with this insect, for which it would be a prior name. 

 However, Wiedemann described melanopogen as having the occi- 

 put, thorax and legs gray-haired, while affinis is especially dis- 

 tinguished among our species of Dasyllis by having the colored 

 hair a peculiar greenish yellow. P. I. 



D. thoracica Fabricius. Common; May 15 to July 20; in copula 

 June 15; has been noted feeding on the rose beetle, Macrodactylus 

 subspinosus. P. I. 



D. grossa Fabricius. Frequent; June 13 to August 22; among 

 the prey is the clover-leaf weevil, Hypera punctata. P. I. 



D. flavicollis Say. The recent separation of the next species 

 from this makes it desirable to give the records in full: Great 

 Falls, Va., May 12, 25, June 20, Banks; May 21, 1914, R. P. 

 Currie; Dead Run, Va., May 19, 23, 1916; in copula, R. C. Shannon; 

 Virginia near Plummers Id., June 2, 1916; Plummers Island, Md., 

 July 7, 1907, McAtee; Falls Church, Va., June 19, Banks; Belts- 

 ville, Md., June 15, 1913, McAtee; July 9, 1916, F. R. Cole. 



D. virginica Banks. Originally described from specimens col- 

 lected at Falls Church, Glencarlyn and Chain Bridge, Va., in 

 June. Great Falls, Va., June 20, 1916, C. T. Greene; July 19, 

 1916, September 21, 1914, J. N. Knull; Cupid's Bower Island, 

 Md., May 31, 1915, feeding on Hoplia trivialis, R. C. Shannon; 

 Falls Church, Va., May 17, reared, May 29, 1913, C. T. Greene; 

 Beltsville, Md., June 28, 1917, L. O. Jackson; Laurel, Md., May 

 3, 1913, E- B. Marshall. 



D. champlaini Walton. Beltsville, Md., July 30, 1916, Har- 

 old Morrison. 



D. posticata Say. Plummers Island, Md., May 30, 1911, J. 

 C. Crawford; Chain Bridge, Va., June 26, 1917, Falls Church, 

 Va., June 16, 1915, on flowers of Ceanothus, C. T. Greene; June 

 22, Banks; Beltsville, Md., June 18, 1916, McAtee. 



Asilinae. 

 Key to the Genera. 



A. Arista pectinate Ommatius. 



AA. Arista not pectinate. 



B. Posterior branch of third vein curving forward meeting costa at or 

 before tip of wing; or the anterior branch angulatcd near its or- 

 igin, or with free stump, or both. 



