146 DIPTERA OF NORTH AMERICA. 



distinguished by its cheeks descending much less beneath the eyes. 

 Front with yellowish-gray dust. Antennas reddish-yellow, the third 

 joint a little infuscated on its apical margin ; bristle with a few rays. 

 Face a little more yellowish than the front, distinctly keeled on its 

 upper half, then moderately convex, and receding a little towards 

 the border of the mouth. Eye-rings downwards rather broad; 

 the uppermost of the bristles, inserted near the eye-rings, is more 

 removed towards the middle of the face. Cheeks remarkably de- 

 scending beneath the eyes for a Discocerina. Palpi pale yellowish. 

 Upper side of the thorax and scutellum rather light ashy-gray. 

 Pleurce more whitish-gray. Abdomen light ashy-gray, appearing, 

 on account of the shortness of the first segment, to consist of four 

 segments, the last of which is at least as long again as the penulti- 

 mate. Femora and tibiae black, the former with the extreme tips, 

 the latter with the base and tip yellowish to a greater extent. Tarsi 

 yellowish with blackish tips. Halteres whitish. Wings whitish, 

 especially if viewed in an oblique direction. Costal vein black, 

 the other veins remarkably paler; the second segment of the costal 

 vein is about half as long again as the third. 

 Hob. Washington. (Osten-Sacken). 



2. D. parva LOEW. 9 . Obscure cinerea, opaca, abdomine nigricante ; 

 antennis, genibus, tibiarum apice tarsisque flavis, alls cinereo-liyalinis. 



Dark ashy gray, opaque, abdomen rather black ; antennae, knees, tibise at 

 their tips and tarsi yellow ; wings grayish-hyaline. Long. corp. 0.07. 

 Long. al. 0.09. 



Though similar to Discoc. lacteipennis, it is easily distinguished 

 by its much smaller size, nearly black abdomen and grayish-hyaline 

 wings not showing any trace of whitish color. Antennae brownish- 

 yellow, second and third joints brownish on the upper margin ; 

 bristle with four or five long rays. Face dusted with whitish-gray, 

 very distinctly keeled on its upper half, farther beneath rather con- 

 vex, and receding a little again towards the border of the mouth ; 

 in proportion to the size of the insect, it is narrower than in Dis- 

 coc. lacteipennis. Eye-rings exceedingly narrow, not becoming 

 broader downwards. Among the bristles standing in its neighbor- 

 hood, the uppermost is a little more advanced towards the middle 

 of the face. Cheeks descending only a little beneath the eyes. 

 Palpi brownish-yellow. Upper side of the thorax and scutellum 

 blackish ashy gray, opaque ; the pleura? likewise. Abdomen gray- 



