110 PROCEEDINGS OF THE NATIONAL MUSEUM. VoL. 62. 
THEREVA USTULATA Krdober. 
1912. Thereva ustulata KrOsER, Stett. Ent. Zeit., p. 265. 
This species is said to be nearly related to egressa Coquillett. No 
specimens have been seen by the writer. 
Type locality.—Laval County, Quebec, Canada. 
Type.—Male, No. 24194, U.S.N.M. 
THEREVA NIGRIPILOSA, new species. 
Male.—Length 10.5 mm. A dull-black species, almost entirely 
black pilose. Head black, occiput gray pollinose, the face and frons 
thickly whitish pollinose; frons, occiput, cheeks, and outer rim of 
face long black pilose, most of the face whitish pilose. 
Thorax black, gray pollinose, brownish on the mesonotum, with 
two faint vittae and the scutellum brown; pile of mesonotum long, 
erect, and black, the bristles black; pleura thickly black and white 
pilose. Halteres black, the stem a little paler. 
Abdomen black, first segment thinly gray pollinose, the others black 
and shining or semishining; posterior margins of segments two to six 
narrowly yellow pollinose. Genitalia in part reddish, black pilose. 
Pile of venter on first three segments whitish, all the rest of the abdom- 
inal pile long, black. Femora black, black pilose, and bristled; tibiae 
reddish, the tips blackish; first tarsal joints largely yellowish as well 
as base of second joint of hind tarsi, the other joints black. Wings 
grayish hyaline, with a black stigma, the costal region and a spot 
just beyond the cell first M—2 smoky; cell M-3 closed in margin, 
R-4 gently curved. 
Type locality—Holotype, a male, bred from larva at Victoria, 
British Columbia, June 15, 1919 (W. Downs), [Canad. coll]. 
Type.—In the National Canadian collection. 
Paratypes.—Two paratypes were examined, both collected at Cran- 
brook, British Columbia, 3,500 feet, June 2 (C. Garrett). One speci- 
men is deposited in the National Museum (No. 25942), the other is 
in the collection of Mr. C. H. Curran. 
This species is in the group with comata, nebulosa, and aurofasciata; 
it differs from nebulosa and comata in the less spotted wings, the large 
extent of the black pile, ete. 
THEREVA COMATA Loew. 
Plate 10, fig. 131; plate 11, fig. 151; and: plate 12, fig. 161. 
1869. Thereva comata Loew, Berlin. Ent. Zeit., vol. 13, p. 7. 
Type locality.—California. 
Type.—In the Museum of Comparative Zoology at Cambridge. 
Without examining the type it is impossible to identify this spe- 
cies with certainty. Grouped around the species we have a complex 
