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



M. clausicella Macquart. Common; June 24 to September 

 25; in copula September 3 and 10; has been found feeding upon 

 Vespula germanica and V. vulgaris. Specimens of this species 

 killed while still in somewhat teneral condition are abnormally 

 colored and have been identified as M. guildiana. This prob- 

 ably accounts for eastern records of the latter form which prob- 

 ably is a western subspecies of clausicella. V. P. I. 



M. orcina Wiedemann. Great Falls, Va., August 11, 1915, 

 McAtee; Maryland near Plummers Id., August 14, 1916, J. C. 

 Crawford; High Island, Md., September 28, Banks; Veitch, Va., 

 August 21, 1917; Falls Church, Va., June 24, 1916, August 14, 1917, 

 September 4, 1915, C. T. Greene; July 28, September 2, Banks; 

 Dunn-Loring, Va., August 30, 1916, Mouth of Four-mile Run, 

 Va., September 17, 1916; Mount Vernon, Va., August 13 and 

 20, 1916, McAtee. Among the prey have been identified, the 

 bumble bees, Bremis impatiens, B. affinis and B. pennsylvanicus 

 and the wasps, Polistes pallipes, Vespula vulgaris and Dolichovespula 

 maculata. 



Promachus Loew. 

 Key to the Species. 



A. Abdomen brown on sides and below, black above; male genitalia with 



silvery hair above bastardii. 



AA. Abdomen conspicuously banded; male genitalia without silvery hair above 

 rufipes. 



P. bastardii Macquart. Great Falls, Va., July 27, Banks; 

 Falls Church, Va., July 21, 1913, C. T. Greene; Glencarlyn, Va., 

 July 2, Banks; Mt, Vernon, Va., July 4 and 13, 1917; Beltsville, 

 Md., July 4, 1916, McAtee. Has been found preying on Vespula 

 vulgaris. 



P. rufipes Fabricius. Common; July 23 to October 3; in cop- 

 ula August 20. P. I. 



Asilus Linnaeus. 



Key to the Species. 



A. Large yellowish species, wings brownish yellow sericeus. 



AA. Smaller, duller species, wings hyaline or in part dusky. 



B. Ovipositor short, rounded, with 4 spines at apex above; male clasp- 

 ers, curved with distinct open space between them; tibiae and meta- 

 tarsi with the basal half or more yellow fuscatus. 



BB. Genitalia otherwise. 



C. Arista of antenna about twice as long as third joint; legs almost 



entirely pale reddish gracilis. 



CC. Arista shorter or only a little longer than third joint; legs with 

 dark markings. 



