122 DIPTEEA OF NORTH AMERICA. [PART II. 



dusky color than the upper side of the thorax. Pleurse with grayish 

 dust upon blackish-green ground. The metathorax is of unusual 

 length and slopes but very gradually, so that the length of the 

 thorax, as compared with that of the abdomen, is unusually large. 

 The color of the abdomen is dusky blackish-green and but little 

 metallic ; the hairs are short and only on the posterior margin of the 

 first segment there are some black hairs of greater length. The 

 black hypopygium is short and stout, sessile, but rather disengaged ; 

 its small outer appendages are lamelliform, blackish-brown and 

 hairy. Fore coxoe long, pale yellow ; on the front side they are beset 

 with so short and delicate white little hairs that they appear gla- 

 brous ; at their tip there are black bristles. Middle and hind coxae 

 yellow, often brownish as far as the tip, especially on the outside. 

 Feet yellow, rather long ; middle and hind femora very slender ; fore 

 femora considerably stronger ; all the tibiae on the under side very 

 bare, otherwise beset with quite short little black hairs ; fore tibiae 

 rather stout, somewhat compressed and curved inwardly, colored 

 with brownish-black upon the latter half of the upper side and most 

 of the hind side thickly bearded with long yellow hairs. Middle 

 and hind tibiaa plain, beset only with few and weak bristles, infus- 

 cated at the end. Fore tarsi black, only at the basis of the first 

 joint brown ; the first joint only a little longer than the second ; 

 the second at the tip with a vestige of a slight compression ; the 

 third joint strongly compressed, broad, bearded on the upper edge 

 with stiff black bristle-like hairs ; the two last joints very short, and 

 of the usual form. Middle tarsi somewhat longer than the tibiaa, 

 the first joint about as long as the other three taken together, yel- 

 lowish-brown with black tip ; the last four joints are black and the 

 middle tarsi on the hind side rather thickly covered with long 

 hairs. Hind tarsi black, about as long as the tibioa, of plain struc- 

 ture and not unusually hairy ; the first three joints are of gradually 

 diminishing length, the fourth about half as long as the third, and 

 the fifth again somewhat longer than the fourth. The teguloe 

 have brown margins with yellowish cilia, which assume, in some 

 directions, a brown tinge. Wings grayish hyaline, long and nar- 

 row with rather strong brownish-black veins ; the first longitudinal 

 vein reaches far beyond the third part of the anterior margin ; 

 second longitudinal vein straight ; the third longitudinal vein at 

 its end only very gently curved backwards ; the posterior trans- 

 verse vein lies far beyond the middle of the wing. 



