332 DIPTERA OP NORTH AMERICA. [PART IT. 



joint red, which, however, in some specimens, can be perceived 

 only at a careful examination. The face rather broad for a male, 

 whitish, on its uppermost part "more yellowish-white. Cilia of 

 the inferior orbit whitish. The lamella? of the hypopygium are 

 dark ochre-yellow and with two flabs, so that, at a superficial 

 glance, the hypopygium appears to have four lamellae ; the longer 

 flab has a narrow black-brown border, is not jagged at all, and 

 beset with some delicate pale hairs. Fore coxa? yellow, a little 

 blackened at the extreme basis only, on the front side with a fine 

 and scattered blackish pubescence. The hind coxa? yellow at the 

 extreme tip only. Feet yellow ; the hind femora with a bristle 

 before the tip. Fore tarsi not quite 1^ as long as the tibiae ; 

 their first three joints yellow, stalk-like, slender, rapidly decreas- 

 ing in length ; the first joint about as long as the three follow- 

 ing together; the two last joints flattened, black and covered 

 with black hair, so as to appear rather broad. The hind side of 

 the hind tibia? only with a very narrow glabrous streak in the 

 shape of a line. Middle and hind tarsi from the tip of the first 

 joint black. Cilia of the tegulae black. Wings grayish-hyaline; 

 the costa without visible swelling at the tip of the first longitudinal 

 vein ; the fourth longitudinal vein not broken. 



Female. Yery much resembling the male. Antennae some- 

 what shorter. Face broader, whitish, not yellowish-white on its 

 upper part. Fore tarsi from the tip of the first joint, blackened. 

 Hob. Palissades, New Jersey ; in June. (Osten-Sacken.) 

 Observation. The female will probably have to be distinguished 

 from the still unknown female of D. scoparius by its larger size 

 and the smaller extent of the black at the basis of the fore coxa?. 



Gen. III. GYMIVOPTERUTUS. 



Corrected Table for the determination of the Species. 



, C Coloring non-metallic. 1 flavus Lw. 



' Coloring metallic, 

 q ( Third joint of the antennae with an elongated point. 2 subulatus Lw. 



t Third joint of the antennae without elongated point. 

 ( Prevailing color of the feet black. 4 



( Prevailing color of the feet yellow. 7 



r Third joint of the antenuse with a very distinct pubescence. 

 4 ] 3 scotias Lw. 



( Third joint of the antennae with a scarcely visible pubescence. 5 



