106 DIPTERA OF NORTH AMERICA. 



rather short ; no impressed spot in its neighborhood ; the short 

 small hairs beneath it are scarcely visible ; eye-rings and cheeks 

 very broad, but the latter a little narrower than in Parydr. bitu- 

 berculata. Antenna? black ; the bristle towards its end excessively 

 slender, being stouter to about its middle, and provided on its 

 upper side with a hardly distinguishable pubescence. Thorax 

 rather indistinctly striped ; the two longitudinal lines formed by 

 fine scarcely visible punctures. Scutellum on its tip with two very 

 approximated conical warts, on the tips of which are the two small 

 bristles usually inserted at the end of the scutellum ; on each side 

 there is a similar tubercle, ending likewise in a small bristle. Tibise 

 and tarsi usually brownish-red, with blackened tips ; but there are 

 specimens with the tibiae quite black and the tarsi brown only at 

 the base, the remainder being quite black ; only in recently devel- 

 oped specimens the anterior side of the tibia? is dusted with white 

 on their whole length ; this white dust is generally interrupted 

 behind the middle of the tibiae. Wings proportionally a little 

 longer than in the other species ; the second segment of the costa 

 is about one-half longer than the third; the last segment of the 

 fourth longitudinal vein is unusually long, showing the trace of a 

 slight convergency towards the third longitudinal vein ; the fifth 

 longitudinal vein is truncated immediately behind the posterior 

 transverse vein ; otherwise the wings are hyaline with a very faint 

 grayish tinge ; the veins are brownish-black as far as the base, or 

 frequently brown or brownish-yellow in the neighborhood of the 

 base ; sometimes this brownish-yellow color on the costal vein ex- 

 tends to far beyond the middle of the wing ; the transverse veins 

 in most specimens are not margined, or show only a trace of black- 

 ish-gray clouding ; but sometimes they have rather broad blackish 

 margins, the surface of the wing being clearer in their neighborhood ; 

 these margins are found particularly in specimens which have a 

 blacker coloration and almost entirely black legs. The deviations 

 are more remarkable than those occurring in the other species of 

 Parydra; but there are various transitions between them, which 

 make it improbable that there is more than one species. 

 Hab. Middle States. (Osten-Sacken.) 



