^2 WILLIsTON: new DIPTfeRA. 



clothed with grayish brownish pollen, but variable in different reflec- 

 tions; when seen from behind, the ground-color is apparent, except 

 on the smooth hind border of each segment; pile of the front segments 

 on the sides white, not abundant; in front of the smooth hind borders 

 of the segments on each side there is a row of white bristles, becoming 

 successively shorter and extending more inwards posteriorly; hypopy- 

 gium shining black. Legs reddish yellow; the femora in front, the 

 tip of the tibiae and all the tarsal joints black. Wings hyaline on the 

 basal portion, with a distinct brownish tinge beyond the basal cells; at 

 the tip tinged with blackish; the submarginal cell from its base and 

 the marginal cell opposite with a distinct brown cloud; the costal and 

 first longitudinal veins distinctly thickened near the tip of the auxiliary 

 vein. 



Length, 15-16 mm. 



Twelve specimens, Washington. A single rubbed female among 

 them has the black on the femora less extensive, and the wings jjure 

 hyaline, except the faint blackish tinge at the tip. 



Asilus fiavipes, n sp. 



Male. Face narrow, thickly covered with white pollen, on the 

 gibbosity above with white black, below with white hair; in profile 

 not very protuberant below, the gibbosity rather more than half of the 

 length of the face, but receding below so that its border is nearly 

 parallelwith the outline of the eyes. Antennae black, the second joint 

 at the tip and the base, and some times nearly the whole of the third 

 joint brownish yellow; the first two joints with black hair, the second 

 joint much shorter than the first, the third as long as the first two, 

 narrowed on its outer part, bristle about as long as the joint. Front 

 with black hair, hardly as narrow above as at the base of the antennae. 

 Occipito-orbital bristles black; beard not abundant, white. Thorax 

 densely covered with grayish white pollen; the two median stripes on 

 the dorsum distinctly separated by a gray stripe, on each side the two 

 usual spots and a smaller one behind; clothed in front with moderately 

 long black hair, behind with rather thin but not stout, black, often inter- 

 mixed with white, bristles; on the margin of the scutellum with four 

 long bristles; vestiture of the pleurae wholly white. Abdomen black, 

 with white hair; rather thinly poUinose, except on the sides and pos- 

 terior margins which are rather broadly gray pollinose. Legs: front 

 femora with a broad black stripe above, not quite reaching the tip, 

 middle femora with a similar stripe reaching the whole length; hind 

 femora wholly black: front tibiae at the immediate tip brown, middle 

 tibiae at the tip distinctly black, hind tibiae for about the distal fourth 

 black; tarsi black, except the base of the metatarsi; elsewhere the 



