OSTEN SACKEN ON WESTERN DIPTERA. 271 



Prevailing pubescence gray : 



6. harrisi (<?).— Atlantic States (?) ,7«*i^ 

 Wings, including the anal angle, infuscated : 



Well-marked brown clouds on the cross-veins, and at the bifurca- 

 tions : 



7. niger ( ).— Georgia. 

 Brown clouds, etc., indistinct or none : 



Abdominal segments with a fringe of whitish hairs posteriorly': 



4. marginatus ( $ ). — California. 

 No fringes of whitish hairs on the abdominal segments, which 

 are deep velvet-black : 

 Small species (8 mm ); stem of halteres pale; knob brown: 



2. luctifer (<?). — Vancouver. 



Large species (15 mm ) ; halteres altogether blackish : 



3. muricatus ( $ ). — Sierra Nevada. 



1. Epibates fitnesttjs n. sp., i .—Deep velvet-black ; wings dark 

 brown along the anterior margin, posteriorly hyaline on the proximal, 

 brownish-hyaline on the distal half. Length 7.5 mm . 



Head, antennae, proboscis, and palpi black ; the frontal triangle and 

 the orbits of the eyes, in a certain light, have a white reflection ; under 

 side of the head with long, white pile ; oral edge, vertex, and occiput 

 with long black hairs. Thorax deep velvet-black, opaque, beset on the 

 dorsum with minute, sharp, rigid points, and sparse, long, black pile; 

 pleurae and coxae clothed with grayish pollen, and sparsely beset with 

 white and blackish hairs. Abdomen deep black, opaque, with some 

 scattered pile on the lateral and under side, which is white at the base 

 and black beyond it. Halteres whitish -yellow, with a brown knob. 

 Legs black. Wings dark brown along the anterior margin as far as the 

 apex, including the first basal, marginal, and two submarginal cells ; 

 from the latter posteriorly, the brown becomes gradually evanescent, 

 until it almost disappears in the last posterior cell ; second basal, anal, 

 and axillary cells hyaline, or almost so ; the surroundings of the an- 

 terior cross-vein are darker brown, those of the stigma still more so ; on 

 the other cross- veins and on the bifurcation of the third vein the clouds 

 are almost obsolete. The denticulation of the costa is almost obsolete. 



Rob.— White Mountains (H. K. Morrison). A single male in Mr. B. 

 Burgess's collection. 



2. Epibates luctifer n. sp., $.— Deep velvet-black ; wings uni- 

 formly brown. Length 8 mm . 



Resembles the preceding in its coloring, but is easily distinguished 

 by the uniformly brown color of the wings, which is only slightly darker 

 on the distal half anteriorly and around the small cross- vein ; denticu- 

 lations on the costa minute, but distinct. Remains of some short, red- 

 dish-golden pile are perceptible on the sides of the thoracic dorsum, 

 especially above the root of the wings. The thorax is beset with the 

 same minute, sharp, rigid points ; the under side of the head with long, 



