120 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



liiud pair, and all the tarsi, brown ; the hind tibiae and tarsi usually 

 darker, nearly blackish. Wings usually dark brown, more blackish 

 toward the stigma, with a large triangular hyaline spot near the tip, 

 reaching from the third vein to the hind margin as far as the tip of the 

 (liscal cell ; the axillary angle, the anal cell, the larger part of the third 

 posterior cell, and somewhat in the discal cell, lighter brown, sometimes 

 wholly hyaline, with a brown band filling out the end of the discal cell 

 {vsiT. fascipennis Macq.), rarely there is a hyaline streak along the mid- 

 dle of the marginal cell; anterior cross vein near middle of discal cell. 



This description is chiefly based upon numerous specimens collected 

 in the vicinity of !New Haven, among which the wings vary very much 

 in the color of the posterior border. Other specimens differing scarcely 

 at all from the more tj pical ones I have from Florida and Kansas. Ac- 

 cording to Dr. Loew, his Ocypt. longiventris differs from fuscipennis in 

 the wings being larger and the picture different, but a large number 

 of specimens show that the coloring of the wings is variable, and, in 

 such frail flies, the size of the wings is a doubtful character. It seems 

 to me very probable that Ocypt. conformis is also a synonym of this 

 species. 



Of the synonyuiy of Ocypt. fascipennis Macq. there can be no doubt, 

 I think. The hyalinity of the wings in extreme examples might indi- 

 <;ate the two varieties to, be " bestimmt verschieden," as Schiner thought 

 (Novara Exped., 34G, 14), but a larger number presents too many in- 

 Termediate forms. 



Baccha aurinota. (Plate IV, tig. 7. ) 



Baccha aurinota (Harris) Walker, List, etc., iii, 548. 



Baccha fascipennis Wiedeuiann, Ansa. Z\v. Ins., ii,96; v. d. Wiilp. Tijdsclir. voor. 

 Eutoiii., xxvi. 



Habitat. — Connecticut, Massachusetts, Indiana! , New York, Canada. 

 $ . Length, 10 to 11™". Face yellow, extending up narrowly on the 

 lower part of the front, more reddish shining in the middle; nearly per- 

 pendicular, and gently concave to the tubercle, thence much receding 

 to the oral margin; cheeks extremely narrow, the eyes approaching the 

 oral margin; the distance between the eyes below not two-thirds the 

 width of the face below the auteuufe. Antennee brown, the under side 

 of the third joint reddish yellow. Front very narrow above, separated 

 only by the width of the ocelli at the vertex; shining black, narrowly 

 ])ollinose along the eyes, above the root of each antenna a reddish yel- 

 low spot more or less confluent, leaving a rounded black spot between 

 the roots of the antennae above. Dorsum of thorax metallic greenish 

 black, with three median, slender, grayish pollinose stripes; pleurae 

 thickly grayish pollinose and with white pile. Scutellum and the hind 

 I)art of the thoracic dorsum, in the middle, shining golden. Abdomen 

 slender, black, shining; the front part of the third and fourth segments 

 with small, interruptvHl, yellowish-red, white pollinose cross-bands; pos- 

 terior portion of the second, tliird, fourth segments, and the remainder 



