PROC. ENT. SOC. WASH., VOL. 23, NO. 5, MAY, 1921 121 



EE. Last vein bent twice or thrice; vein 3 close to and nearly 

 paralleling costa, in nearly a straight line from the radial 

 crossvein to costal margin; radial crossvein nearer end 

 of second vein; subcostal cell usually smaller than 

 costal; halteres dark; hind tibiae not so expanded 



. Rhegmoclema. 



CC. Apical cell lacking; i. e., anterior branch of fourth vein inter- 

 rupted basally. 



F. Last vein simply curved; third vein curved remote 

 from costa; radial crossvein at about middle of 

 second vein; subcostal cell much larger than costal 



Anapausis. 



FF. Last vein bent twice; third vein straighter, nearer 

 costa; radial crossvein between 4th and last fifths 

 of second vein; subcostal cell much larger than 

 costal... Aldrovandiella. 



SCATOPSE Geoffrey . 



The genus Holoplagia Enderlein (Zool. Anz. Bd. 40, No. 

 10-11, Oct. 18, 1912, p. 267), for the separation of which from 

 Scatopse, the chief character is that the crossvein between veins 

 3 and 4 is complete, would appear untenable since all degrees of 

 completeness of the vein may be found in a single species 

 Scatopse not at a. A new species is here described that has no 

 part of a crossvein (in the specimens thus far examined) but only 

 a hump at a point in anterior branch of fourth vein corresponding 

 to the origin of the stump or crossvein of species having one. 



Key to the species. 



A. With a more or less complete crossvein between anterior branch of 4th 

 vein and 3d vein; tibiae black usually with a brown annulus.... ...notata. 



AA. No crossvein, but anterior branch of 4th vein distinctly angulate at 

 point corresponding to origin of crossvein in last species; tibiae and 

 tarsi chiefly pale. 

 B. Joints 3-6 of antennae pale; tibiae with only narrow rings of dark 



color varicornis. 



EE. Antennae wholly black; dark annuli on tibiae broader on each suc- 

 ceeding pair of legs posteriorly, the hind tibiae about half dark 



.. tibialis n. sp. 



Scatopse notata Linnaeus. 



One of the most common species; has been taken in Virginia 

 near Plummers Id., Oct. 19, 1914, R. C. Shannon; Plummers Id., 

 Md., ( >ct. 26, 1906, A. K. Fisher; Maryland near Plummers Id., 

 April 28, 1914, on flowers of wild plum; Cabin John, Md., April 

 14, 1916, R. C. Shannon; Berwyn, Md., April 1, 1 ( >17, on 

 flowers of Salix capraea, McAfee; Cleveland Park, 1). C., April 

 14, 1918, H. I, Viereck; Washington, D. C., November 2, 1906, 



