AKTll. NOTES ON NEARCTIC BIBIONID FLIES McATEE. 19 



DILOPHUS BREVICEPS Loew. 



Dilophus breviceps Loew (H.), Dipt. Amer. sept, indig.. Cent. 9, No. 59, 

 1869, CompL Works, voL 2, p. 200 [New Hampshire]. 



Male. — Eyes with short dark hair, head and body shining black 

 with longer pale hair; genital segment with a U-shaped cleft half its 

 length, superior plate about as long as wide across hind margin 

 which is very slightly convex ; legs brownish black the fore femora 

 darkest, hair of legs generally pale, tending to be darker on tarsi 

 especially the front ones; wings nearly hyaline, veins near costa 

 yellow-brown, stigma nearly obsolete. 



Female. — Head black, basal joint of antenna in part or wholly 

 pale; thorax yellow to rufous, sometimes touched with brown to 

 black on pleura, front of prothorax, and scutellum; abdomen vel- 

 vety brown to black above, sordid yellow to brown below ; coxae and 

 femora yellow, tibiae and tarsi pale fuscous the anterior darker, the 

 front tarsi sometimes black ; hair pale with the exception of that on 

 front tarsi which is dark ; halteres with the knob fuscous, the stalk 

 pale; wings yellowish fumose, the veins nearly concolorous, those 

 near costa sometimes darker; stigma large, light to dark brown. 



Length of wing, 3.5-4.5 mm. 



Three females from North Carolina examined and a male and fe- 

 male labeled Mannanattawa, June 25, 1903, W. J. Wilson. 



DILOPHUS CAURINUS. aew •p«eiea. 



Male. — Entirely shining or subshining black, eyes with copious 

 long dark hair, hair of other parts of body and of coxae and femora 

 long, pale; of tibiae and tarsi shorter, more bristly, tending to be 

 darker especially on tarsi; genital segment cleft about half its 

 length, the cleft often distinctly expanded at bottom, superior plate 

 only about three times as long as wide along hind margin which is 

 slightly concave; wing grayish hyaline, veins near costa and large 

 stigma pale brown. 



Female. — Head and thorax black, abdomen brown, with pale hairs; 

 humeri, front (sometimes all) coxae, and femora yellow to rufous 

 with pale hair, tibiae and tarsi brownish to black, color of hair corre- 

 sponding to depth of coloring of joints; halteres with pale stalks and 

 dark knobs ; wings clear to yellowish hyaline, sometimes with trans- 

 verse dusky clouding at level of stigma, veins near costa and stigma 

 brownish, others nearly hyaline. 



Length of wing, 4.5-6 mm. 



Type.— Csit. No. 24701, U.S.N.M. A male, Popoff Island, Alaska, 

 July 12, 1899, T. Kincaid (U.S.N.M.). 



Paratypes of both sexes, Friday Harbor, Washington, July 17-23, 



1905, May 29, June 1, 1906; San Juan Island, Washington, May 31, 



1906, and Seattle, Washington (Aldrich). 



