10 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.60. 



A male collected in the Graham Mountains, Arizona, June, 1914, 

 E. G. Holt, is identified as this species ; the size is rather larger than 

 the type according to Bellardi's measurements, but size is very 

 variable in Bibio; in other characters the specimen agrees well with 

 the original description. 



BIBIO FEMORATUS Wiedemann. 



Bibiio] femorata Wiedemann (C. R. W.), Auszereuropaische zweifltlgellge 



Insekten, vol. 1, 1828, p. 79 [North America]. 

 Bibio fuscipennis Macquabt (J.), Dipteres nouveau ou peu connus, vol, 1, 



pt. 1, 1838, p. 87 [North America]. 



Male. — Head, body, and coxae black; legs black, the femora ex- 

 cept their extremities, the anterior tibial spurs, bases of tarsal 

 joints, especially the anterior ones, rufous (occasional specimens 

 have a greater proportion of legs pale) ; long hairs of body and 

 legs pale, those of head darker ; wings chiefly hyaline. 



Female. — ^The female differs in having the shorter hairs of head 

 pale and the winga smoky to black. 



Length of wing, 7-9 mm. 



The inner spur of front tibia varies more in length than is usual 

 in other species, sometimes being only about half the length and 

 scarcely deserving to be called subequal to the outer. 



The known range of the species extends from New Hampshire, 

 Michigan, and Colorado to Missouri and Virginia. Specimens from 

 most parts of this range have been examined in connection with the 

 preparation of this paper. 



BIBIO FRATERNUS Loew. 



Bihio fratemus Loew (H.), Dipt, Amer. sept, indig,, Cent. 5, No. 8, 18(J4. 

 Conipl. Work, p. 236 [District of Columbia]. 



Male. — Head, body, and coxae black, the eyes with dark and other 

 parts with pale hair; femora and succeeding leg joints yellow to 

 rufous, dark-tipped; wings chiefly hyaline, anterior veins and 

 stigma dark. 



Female. — The female differs in having shorter hairs generally, 

 all of them pale ; anterior parts of pronotum and mesonotum, except 

 for three more or less distinct dark vittae, sometimes part of pleura 

 and the coxae, yellow to rufous ; wings f umose. 



In both sexes, the front tibiae are almost wholly black, the rufous 

 spurs subequal, and the hind metatarsi equal or exceed in length the 

 succeeding 3 tarsal joints combined. 



Length of wing, 5-6.5 mm. 



Specimens examined come from a range with the following States 

 at its extremes : Connecticut, Iowa, Tennessee, and Virginia. 



