20 PEOCEEDINGS OF THE NATIONAL MUSEUM. vou 60. 



DILOPHUS EMARGINATUS. new species. 



Male. — Body shining black, legs more brownish, the front tibiae 

 darker; close-set hair of eyes dark, longer hair of underside of 

 head, body and greater part of legs pale, of front tibiae and tarsi 

 dark; genital segment with a cleft half its length, rounded expanded 

 at the bottom, superior plate decidedly not transverse, about as long 

 as wide across hind margin which is distinctly angularly emargi- 

 nate ; wings hyaline, veins near costa brown, stigma nearly obsolete. 



Female. — Humeri obscurely castaneous, thorax otherwise, and 

 head shining black, abdomen velvety brownish black; legs rufous 

 more or less suffused with brown, the front coxae and femora palest ; 

 all hairs pale; wings hyaline, veins near costa and distinct stigma 

 brown. 



Length of wing, 4.5 mm. 



Type.— C?it. No. 24702, U.S.N.M. Male and allotype collected at 

 Samoa, California, May 23, H. S. Barber (U.S.N.M.). 



DILOPHUS OBESULUS Loeir. 



Dilophus obesulus Loew (H.), Dipt. Amer. sept, indig., Cent. 9, No. 60, 

 1869; Compl. Work, vol, 2, p. 200 [District of Columbia]. 



Male. — Lower surface of head black with long pale hair, eyes with 

 shorter more abundant dark hair, thorax and abdomen shining black 

 with long, sparse, pale hair; genital segment with a U-shaped cleft, 

 about half its length, superior plate transverse, about four times 

 as broad as long, its hind margin slightly concave; legs reddish 

 brown to black, in general pale haired but hairs on tibiae and tarsi 

 (especially the front ones) often in part or wholly dark; wings 

 and veins nearly hyaline, slightly fumose costally, stigma almost 

 obsolete. 



Female. — Head black with short pale hair ; humeri rufous, thorax 

 elsewhere above shining black with sparse pale hair; pleura brown- 

 ish-black more or less spotted with paler; abdomen velvety brown- 

 ish black with abundant pale hair; coxae and femora (and sometimes 

 the front tibiae) yellow to rufous, pale haired; trochanters, tibiae 

 (except front pair occasionally) and tarsi, fuscous to black chiefly 

 darker haired ; wings nearly hyaline, veins near costa brown, rather 

 large stigma nearly black. Females from western localities usually 

 have more or less dusky clouding transversely in the wing as the 

 level of the stigma. 



Length of wing, 4-5 mm. 



Specimens examined are from Plummers Island, Maryland, Great 

 Falls and Dead Run, Virginia ; Cochetopa National Forest, Colorado, 

 and Mott, North Dakota (Biological Survey) ; Pennsylvania, La 

 Fayette, Indiana, and Moscow, Idaho (Aldrich). Two males from 

 British Columbia (U.S.N.M.) are very similar, but I do not care 

 to record them definitely as D. obesulus. 



