126 PROCEEDINGS OF THE NATIONAL MUSEUM. vob. 62. 
yellow and long yellow pilose. Venter almost entirely yellow, the 
segments narrowly black at the base. Basal two-thirds of femora, tip 
of tibiae, and two basal joints of tarsi black, other parts of the legs 
yellowish; front femora with black and yellow pile below, the two 
hind pairs with only yellow pile, largely reclinate. Wings gray hya- 
line, R—4 distinctly curved, cell M-3 closed before the margin; a faint 
gray cloud on the anterior cross vein; stigma yellowish brown. 
Type locality.—Huntington Lake, Fresno County, 7,000 feet, July 
26, 1919 (K. P. Van Duzee). 
Type.—Male, in the California Academy of Sciences. 
THEREVA BOREALIS, new species. 
Female.—Length 11 mm. Head black; upper half of frons brown- 
ish pollinose, the lower part and face silvery white; a few short black 
hairs on the upper part and above the antennae; pile of face very 
short, white; cheeks and occiput white pollinose and pilose, the bris- 
tles on latter black. Antennae short, black, the first joint about as 
long as the third, gray pollinose, with white pile basally and a few 
apical black bristles. 
Thorax black, mesonotum gray pollinose, with two distinct whit- 
ish vittae on the blackish gray dorsum. Scutellum, pleura, and coxae 
black, gray pollinose, white pilose. Mesonotum with mixed short 
black and white pile. Halteres yellowish at base and tip, base of 
knob blackish, the knob gray pollinose. 
Abdomen black, largely shining black; first segment gray pollinose, 
with narrow silvery gray posterior margins on the second and third 
segments; fifth and sixth silvery gray pollinose except the base. 
Venter gray pollinose. Pile of abdomen short and sparse, white and 
reclinate on the first three segments, black and erect on the others. 
Femora black, very short silvery white pilose; front tibiae except 
base and the tarsi blackish; base of the front tibiae, most of the four 
hind tibiae, and base of tarsi yellowish. Bristles of the legs black. 
Wings hyaline, the veins and stigma brown and very narrowly bor- 
dered pale brown; cell M-3 broadly open in the margin. 
Type locality.— Michigan Agricultural College, May 9, 1901. 
Type.—Female, in the Cornell University collection. 
THEREVA NITORIS Coquillett. 
1894. Thereva nitoris CoquiLuETT, Journ. N. Y. Ent. Soc., vol, 2, p. 101. 
The unique female type is the only specimen known. ‘The species 
is evidently related to the new form described above. 
Type locality.—Missouri. 
Type.—Female, No. 993, U.S.N.M. 
