198 PROC. ENT. SOC. WASH., VOL. 20, NO. 9, DEC., 1918 



C. sequax Williston. Maryland near Plummers Island, August 

 22, 1916, McAtee; Marlboro, Md., June 19, 1916, R. C. Shannon; 

 Falls Church, Va., male August 2, Nathan Banks; August 12, 1912, 

 C. T. Greene; Washington, D. C., August 19, 1911, F. Knab. 



C. stria tus Osten Sacken. Great Falls, Va., June 27, 1909, 

 F. Knab. 



C. univittatus Macquart. Very abundant; season, May 31 

 to August 10. Males taken at Falls Church, Va., June 19 (on 

 Ceanothus), and July 23; at the same locality also a female on 

 chinquapin flowers, May 30, and another, at honey dew on tulip 

 tree, July 12, Nathan Banks. (P. I.) 



C. vittatus Wiedemann. Very abundant; extreme dates, 

 June 4 and September 10, thus being taken later in the fall than 

 any other Chrysops. (P. I.) 



C. vitripennis Shannon. Originally described from Belts- 

 ville, Md. Taken there June 9, 1915, Nathan Banks; June 18, 

 1916, McAtee; June 25, 1916, R. C. Shannon; July 6, 1916, F. R. 

 Cole. This species inhabits the peculiar Powdermill bogs, and 

 seems to spend all its time on grass and other vegetation only a 

 few inches above the water surface. Its flight is slow and feeble, 

 and its whole behavior differs widely from that of all the other 

 local species of the genus. 



Merycomyia Hine. 



M. whitneyi Johnson. 



Tabanus whitneyi Johnson, C. W., Psyche, Vol. 11, pp. 15-16, 

 Feb. 1904; [Wellesley, Mass., N. Y.]. 



Merycomyia geminata Hine, J. S., Ohio Naturalist, Vol. 12, 

 No. 7, May 1912, pp. 515-516. 



A single female of this interesting species was collected at Dyke, 

 Va., July 16, 1916, McAtee. 



Tabanus Linnaeus. 



These are the horse-flies all but 2 species of which are vigorous, 

 swif t-flying, robust insects. T. bicolor and T. flavus are soft-bodied 

 and weak-winged compared to the others, and they are crepuscu- 

 lar in habit. Only one of our species habitually attacks man. 

 namely T. pumilus. T. costalis, T. nigrovittatus, and T. lineola 

 share this habit to some extent, joined occasionally by the larger 

 species, as T. sulcifrons. 



Key to the Species. 



A. Body almost entirely yellowish; wings weak, hyaline, with yellow- 

 ish costa; unusually soft, feeble species. 



B. Anterior branch of 3rd vein ending in a free stump, joined to 

 posterior branch by a short cross-vein; all cross-veins dark 

 clouded . . flavus 



