April, 1907.] Robber Flies of the Genus Philonicus. 117 
are not so prominent as in some of the other species of the genus. 
Wings hyaline; legs largely reddish, coxae colored like the thorax, 
femora with more or less black on the outer side, especially on 
apical half; tibiae and metatarsi black at apex, other tarsal seg¬ 
ments mostly black. Abdomen dull black, before the incisures 
with narrow white bands, in the front margin of which there 
are on either side in each two or more bristles. 
Length, 17 millimeters. Male and female taken in south¬ 
western Colorado, July 14th, 1899, by E. J. Oslar. 
Philonicus obscurus n. sp. General color dark with the wings 
pale fumose all over. The abdomen has different shades accord¬ 
ing to the view taken. Gibbosity of the face small with a few 
bristles, part of which are black and the others white; face with 
gray pollen, front with some small black bristles and occiput 
above with a row of black bristles; antenna black, first segment 
longer than the second, third, exclusive of the arista, about as 
long as the other two; arista a little shorter than the third seg¬ 
ment. Thorax brownish gray pollinose, with a middorsal dark 
brown stripe narrowly divided before, and on either side two 
spots of the same color, one before the transverse suture and the 
other behind it. Wings uniformly darkened all over, but it 
would not be far wrong to say they are hyaline. Legs black and 
reddish; coxae colored like the sides of the thorax, femora 
entirely black except that the posterior ones are often narrowly 
yellowish at the extreme base; tibiae reddish at the base and 
black at the apex; the extent of these two colors on the tibiae 
is somewhat variable, the tendency being for the black to be 
most extensive on the outside and the reddish on the inside; 
feet with the first two segments reddish on basal part, other 
segments usually entirely black. Abdomen opaque black, 
before the incisures with gray bands, in the front margin of each 
of which on either side are two or more distinct bristles. 
Length, 13-16 millimeters. A male from Kentucky, across 
the river from Cincinnati, collected by Chas. Dury, two females 
from Washington, D. C., and males and females from Riverton, 
N. J. and Pendleton, N. C. procured from Prof. Chas. W. Johnson. 
Philonicus rufipennis n. sp. Gibbosity of the face small, fur¬ 
nished with a few bristles which usually are all white, but in 
one or two of the specimens studied there is now and then a black 
bristle intermixed; face and front with silvery pollen; a row of 
black bristles on the occiput above; first segment of the antenna 
black, second largely yellowish and shorter than the first, third 
black, not quite as long as the first two together, arista slender, 
about the length of the third segment; beard entirely white. 
Thorax gray pollinose, with a middorsal brown stripe narrowly 
divided before, and two spots of the same color on either side, 
one before and the other behind the transverse suture; coxae 
