200 Annals Entomological Society of America [Vol. IX, 



hind femora with some black, mostly above; wings brownish; halters 

 yellow. In structure very close to D. nigriceps and D. picta; in the 

 venation the second vein ends nearer to the first vein than in D. picta; in 

 this respect similar to D. nigriceps. 

 Length, 7 mm. 



From Corvallis, Oregon, 4, 6 June (Lovett). Cotypes in 

 collection Ore. Agr. College and that of author. Differs at once 

 from D. picta and D. nigriceps in the much greater extent of the 

 yellow on the abdomen. 



Our four species may be distinguished as follows : 



1. Humeri dark;scutellum dark; small species vitiosa 



Humeri pale, scutellum more or less pale 2 



2. Second and third segments yellow with four basal black spots; scutellum 



yellow pacifica 



Second and third segments mostly black, with apical yellow margin, more or 

 less indenting the black 3 



3. Scutellum yellow; Eastern species nigriceps 



Scutellum mostly dark; Western species picta 



Local Species. 



The following eighteen species have been taken in Northern 

 Virginia at, or in the vicinity of, Falls Church. Of the eighteen, 

 thirteen have been taken in June, two (Myopa) only before 

 June, and three only later than June. Almost invariably they 

 occur only on white blossoms; Myopa in early spring has been 

 taken on red bud, but prefers amelanchier. 



Physocephala tibialis Say. Fairly common, 14 June to 17 Sept. 



Physocephala sagittata Say. Falls Church, 17 June to 8 July. 



Conops brachyrhynchus Lw. Falls Church, 16 June to 6 July. 



Conops xanthostomus Will. Falls Church, 5 July to 8 Sept. 



Conops sylvosus Will. Falls Church, 9 May to 15 July. 



Myopa vicaria Walk. Falls Church and Great Falls, 15 April to 

 27 May. 



Myopa vesiculosa Say. Falls Church and Great Falls, 10 to 27 

 April. 



Myopa virginica Bks. Falls Church, 15 June to 7 July. 



Occemyia abbreviata Loew. Common, 22 May to 31 July. 



Occemyia loraria Loew. Common, 14 June to IS Sept. 



Zodion fulvifrons Say. Common, 13 June to 24 Sept. 



Zodion perlongum Coq. Falls Church, 6 to 21 Sept. 



Zodion sayi Bks. Falls Church, (3 July to 27 Sept. 



Zodion nanellum Loew. Two from Falls Church, Great Falls, 

 16 June, 7 Sept. 



Zodion parvum Adams. Three from Glencarlyn, 24 June, 2 July. 



Dalmannia nigriceps Loew. Great Falls, Glencarlyn, 5 and 7 June. 



Dalmannia vitiosa Coq. Falls Church, Glencarlyn, 14 and 17 June. 



Stylogaster neglectus Loew. Falls Church, Great Falls, Glencarlyn, 

 14 June to 27 July. 



