-410 PROCEEDINGS OF THE NATIONAL MUiiEUM. vol. o8. 



• RHIPIDIA SHANNONI Alexander. 



Great Falls, Virginia, October 21, Nathan Banks; Dead Kun, Vir- 

 ginia, October 28, 1919, McAtee; Pliimmers Island, May 19, 2G, 1914, 

 at light, June 14, 1913, July 4, 1913, K, C. Shannon; July 21, Septem- 

 ber 5, October 22, 1915, September 13, 1914, McAtee; August 8, 18, 

 1912, J. R. Malloch ; Cabin John, Maryland, August 30, F. Knab. 



Genus DICRANOMYIA Stephens. 



KEY TO SPECIES. 



1. Wings very long and narrow, lanceolate D. loiifjipennis (p. 412). 



Wings broad, not lanceolate 2. 



2. Sc ending opposite, or before, or but slightly beyond the origin of the 



sector 3. 



Sc ending far beyond the origin of the sector 13. 



3. Antennae with at least the basal segments pale 4. 



Antennae with the segments dark throughout 7. 



4. Cell first Mz open, the hi cross-vein lacking 6. 



Cell first M2 closed 5. 



5. Flagellum of the antenna and the halteres pale D. piidica (p. 412), 



Flagellum of the antenna and the halteres brown D. diversa (p. 411). 



6. Praescutum with a single brown stripe; dorsal pleural appendage of the 



male hypopygium a short hook D. imtiiodesta (p. 412). 



Praescutum with three brown stripes ; dorsal pleural appendage of the male 

 bypopygium a strong, saberlike hook which touches its mate of the oppo- 

 site side D. (jhnUator (p. 411). 



7. Cell first M2 open ; Sc far before the origin of Rs due to the shortness of 



the latter, which is about equal to the basal deflection of i?4+5 



D. hreriveiia (p. 411). 



Cell firsit Mi closed ; Sc nearly opposite the origin of Rs, which is much 



longer than the basal deflection of Ri*f> 8. 



8. Thorax shining black, the pleura with a grayish pruinosity 



D. morioides (p. 412). 

 Thorax not shining black ; gray, brown, or yellowish brown 9. 



9. Femora brown with the tips broadly yellow; wings marked with brown 



along the veins D. badia (p. 411). 



Femora not banded with yellow ; wings unmarked or nearly so 10. 



10. Sci much longer than Sca, being nearly, if not quite, the length of the 



stigma D. distans (p. 411). 



SCi short, not more than one-half the length of the stigma 11. 



11. Coloration gray, the praescutum with a broad median brown stripe; a 



narrow brown seam on r D. liberta (p. 412). 



Coloration brown or yellowish brown; no narrow brown seam on r 12. 



12. The basal deflection of M1+2, forming the inner end of cell first M2, is 



arcuated so that cells first M2 and R3 are almost on a line 



D. stulta (p. 412). 

 The basal deflection of iT/1+2 is not conspicuously arcuated, cell first M2 beinp; 



conspicuously more distant from the wing base than cell Rz 



D. hacretica (p. 412). 



33. Wings spotted with darker 14. 



Wings unmarked, except for the stigmal spot when present 15. 



