psilopus. 240 



are once and a half the length of the tibiae, in the 9 only about 

 once and a third ; their first joint is very elongated, so that it is 

 much longer than the remaining joints taken together; besides the 

 usual short pubescence, which is much longer upon the hind side in 

 the g than in the 9 , it has a few small black bristles upon the under 

 side. Middle tibiae in the 9 with but a few black bristles upon 

 the upper and front side ; in the g besides with a row of erect 

 bristles inserted almost on the under side and running from the 

 base to the tip. Middle tarsi of the same coloring as the fore 

 tarsi, still the black coloring begins generally somewhat earlier in 

 the J" ; they are about once and a half the length of the tibiae ; 

 the first joint alone is not much shorter than the tibia and nearly 

 \\ the length of the following joints taken together ; beside the 

 usual minute hairs, it has upon the under side about seven short 

 black bristles, upon the anterior side one or two somewhat longer 

 ones ; the middle tarsi of the 9 are of the same structure, but some- 

 what shorter, and the small bristles on their first joint are smaller. 

 Hind tibia? at the extreme tip black, with the ordinary pubescence, 

 upon the outside with three or four bristles ; hind tarsi shorter 

 than the hind tibiae, entirely black, the first joint once and a half 

 the length of all the following taken together, which are of a gra- 

 dually decreasing length. The small tegulae with black border and 

 with long black cilia. Halteres yellowish ; the basis of the peduncle 

 blackish. Wings hyaline ; costa with the usual short pubescence ; 

 the black picture not very extended ; the two blackish bands 

 have no connection behind the fourth longitudinal vein ; the first 

 band is not seldom interrupted immediately before the fourth 

 longitudinal vein, and the second is never extended as far as the 

 apex. Hind transverse vein moderately oblique, somewhat 

 sinuated ; the basis of the anterior branch of the fourth longitu- 

 dinal vein is nearly twice nearer to the margin of the wing than 

 the hind transverse vein. This branch has, at its origin, a some- 

 what recurrent direction, and turns from there towards the mar- 

 gin at a right angle, which is rounded at the tip ; it reaches the 

 margin somewhat before the apex in the immediate proximity of 

 the tip of the third longitudinal vein. 



Hab. Pennsylvania, Georgia, Virginia, Illinois, etc. 



Observation 1. — I possess a g , which is distinguished from all 

 others, the row of bristles, peculiar to the sex, upon the lower 

 part of the front side of the middle tibiae being much closer, and 



