38 AMERICAN BLACK FLIES OR BUFFALO GNATS. 



Simulium bracteatum Coquillett. 



Female. — Opa(iue black or brown-black; basal two joints of an- 

 tennae yellow, palpi black-brown. Prescutum and margin of scutum 

 bordering on it yellowish, pleura brown, yellowish posteriorly, 

 darker on lower central portions, scutellum and postscutum black- 

 brown. Abdomen opaque black-brown. Legs yellow, darkened on 

 apices of all femora and tibiae, entire fore and mid tarsi except ex- 

 treme base of latter, and apices of first and second and all remaining 

 joints of hind tarsi. Wings clear, thick veins yellowish brown. 

 Halteres pale yellow, darkened at base of stalk. 



Frons rather narrow, sides divergent, less than one-third the width 

 of head at upper angle of eyes, and more than one-half as wide at 

 lower angle as at upper, surface covered with close-lying, thickly 

 placed, brassy yellow, scalelike pilosity; face paler in color than 

 frons and equal to it in length, distinctly longer than broad, pilosity 

 rather paler and looser than that of frons, antennal pilosity pale; 

 hairs on palpi brownish. Scutum unstriped, pilosity very close, 

 rather scale-like, brassy yellow in color; pleural tuft pale yellow; 

 scutellum with close-lying yellow pilosity and long, upright yellow 

 hairs ; postscutum with yellow pilosity. Abdomen with close pilosity, 

 on all segments, of a similar nature to that on mesonotum, apical 

 segment with longish hairs. Legs with close-lying yellow pilosity 

 on the yellow parts, which is longer on the dorsal surfaces, and brown 

 hairs and pilosity on the dark portions ; claws as in Plate II, figure 14 

 {Prosimulium pecuarum) ; hind tarsi with basal joint produced at 

 apex and second with scale and basal constriction. 



Lengtli, 2.5-3 mm. 



Redescribed from type specimens, Cambridge, Mass., May 31, 1869. 

 There is also one female in the collection from Plummers Island, 

 Md., April 19, 1903 (H. S. Barber), one female from Franconia, 

 N. H. (Mrs. A. T. Slosson), and one female from Los Angeles, Cal. 

 (collection Coquillett). 



There are several males and one female in the collection of the 

 Illinois State Laboratory of Natural History from Algonquin, 111. 

 (Nason). 



Male. — Opaque black. Head in type broken off. Scutum with 

 indistinct anterior whitish dusting, prescutum yellowish, pilosity 

 brassy yellow, rather more hairlike than in female and distinctly 

 longer, lateral margins of scutum broAvnish, pleural tuft pale yellow, 

 scutellar pilosity and hairs long, yellow, postscutum bare. Abdomi- 

 nal basal fringe long, yellow, all segments with long yellow pilosity, 

 that on basal four segments laterally very thickly placed and adher- 

 ing closely to surface, apical four segments with pilosity much 

 shorter and sparse. Legs brown, apically the joints slightly dark- 



