142 DIPTERA OF NORTH AMERICA. [PART IV. 



cell ; stigma large, brown, square ; all the veins dark brown ; 

 discal cell present ; the seventh longitudinal vein is sinuated in 

 the middle ; its latter portion is rather approximated to the sixth 

 vein ; the great cross-vein is usually before the middle of the 

 discal cell. 



Hab. Washington, D. C. ; Trenton Falls, "N. Y. Occurs com- 

 monly in the spring and in autumn, and may be seen in copulation 

 at both seasons. 



R. fascipennis Zett., evidently allied to R. nubilus, and origi- 

 nally found in Norway, has been also received from Greenland 

 (Stseger, Grceril. Antliater in Krojer's Tidskrift, etc. 1845, p. 

 355, 16) ; its description from Zetterstedt, Dipt. Scand. X, p. 

 37 77, is reproduced in the Appendix I. 



2. R. illilOCeilS, n. sp. % and 9 • — Fuscano-cinereus, vittis thoracis 

 indistinctis ; alarum cellulis omnibus crebre fusco-maculatis ; cellule 

 discoidali clausa ; venis longitudinalibus sixta et septima divergentibus. 



Brownish-gray ; stripes of the thorax indistinct ; all the cells on the wings 

 densely spotted with brown ; discal cell closed ; sixth and seventh longi- 

 tudinal veins divergent. Long. corp. 0.2. — 0.25. 



Brownish-gray ; antennae and palpi blackish ; stripes of the 

 thorax very indistinct ; abdomen grayish-brown ; male forceps 

 reddish-brown, with strong, short, black horny appendages ; 

 halteres somewhat infuscated ; feet brownish ; tip of the femora 

 darker. Wings grayish, with dense brown dots in all the cells ; 

 several larger brown spots along the anterior margin ; in the 

 intervals of these spots, the costal and first longitudinal veins 

 are pale yellow. Discal cell closed ; the sixth and seventh longi- 

 tudinal veins are throughout strongly diverging, and thus the 

 axillary cell is much broader at the tip than in the middle. 



Hab. Washington, D. C, in April ; New Jersey. 



In some specimens the spots are less dense in some of the cells, 

 especially in the basal ones. 



3. R. nigrlpilus, n.sp. % and 9. — Fuscano-cinereus; alisimmacu- 

 latis ; cellula discoidali clausa ; venis longitudinalibus sixta et septima 

 divergentibus ; antennarum basi pallida. 



Brownish-gray ; wings immaculate ; discal cell closed ; sixth and seventh 

 longitudinal veins divergent ; basis of the antennae pale. Long. corp. 

 0.2—0.22. 



