3S6 C. n. OSTEN SACKEN'S PRODROME 



tmlinal vein; basal cells iiifuscatcd nt the iiroximal ends cnly; Lody aUogellicr Lrowni^li-ycllo^v, .■ibdonicn 

 browiiisli above, with yellowish hind margins and triangles; lliorax Avith three pale brown dorsal stripes. 



Length, 9-10 nun. 



$ . In all respects, excejit the sexual characters, similar to the fcm:\lc. 



Length, 8 mm. 



Female. Altogether l.)rowni^;li-yellow ; face yellowish-ferruginous, including the Atcial 

 callosities and cheeks; frontal callosity yelloAvish-red ; pollen rotuul the antennae and on the 

 facial orbits yellowish-Avhite ; on the front more yellowish. Antenna^: first two joints yel- 

 lowish, beset with black hair ; third joint comiiaratively short, reddish, its latter half dark 

 brown. On the brownish-yellow, in some specimens grayish ground-color of the thorax, 

 there are three brown dorsal stripes, the intermediate one narrower, linear; other brown 

 stripes betw'een the roots of the wings and the lumieri and in the middle of the pleur;e ; 

 pectus Ijrown. Scutellum ^-ellowish-brown, often with a grayish tinge at the basis or on the 

 sides. Abdomen pale brownish ; first segment and base of the second yellowish, leaving a 

 broad, subtriangular brownish spot, which occupies the whole posterior half of the second 

 seo-ment; a yellowish triangle in the middle of the hind margin; the following segments 

 have more or less broad, jellow, hind margins expanding into pale jellow triangles in the 

 middle ; in some specimens, -where the brown is more saturate, the yellow' hind margin 

 emits on each side of the triangle an oblique yellow streak, traversing the brown ; the 

 intensity and distinctness of the coloring of the abdomen is very variable. Feet reddish- 

 yellow, end of front tibia?, front tarsi and the ends of all the other tarsi, brownish. Ilal- 

 teres brownish-yellow. The picture of the Avings varies from pale brown to brown ; the 

 costal cells and the stigma are yellowish-brown; the two basal cells are infuscated on the 

 proximal half; the first more than the second ; the crossljand touches the hind margin and 

 fills out the fourth posterior cell ; the last section of the fifth vein is enveloped in a brown 

 cloud, which partly fills out the distal end of the anal cell, and also communicates with the 

 crossband across the proximal half of the fifth posterior cell ; the distal half of the anal 

 ano-le has a grayish tinge ; its proximal half and those portions of the anal cell and of the 

 basal cells, which are not infuscated, are whitish hyaline; the apical spot is coalescent with 

 the crossband in the marginal and on the anterior portion of the first submarginal cell; it 

 does not reach beyond the anterior half of the second submarginal cell ; the triangular 

 hyaline space between the crossband and the apical spot is more or less tinged with gray in 

 different specimens ; the more gra}' it is, the more the whitish halo along the margin of the 

 cros.sband becomes apparent. 



3Iah. Except in the usual sexual characters, it does not differ from the female. 



Hah. Newport, R. I., in August; Maryland (Uhler); British America (Scudder). I 

 caught the male in Central Park, N. Y., Sept. 6, 18G9. Seven females and one male. 



Wiedemann's synonymy seems certain ; Walker's is probable, although doubtfid ; some 

 omission must have occurred in his description of the frontal callosity and of the anten- 

 na;. I have mentioned tibove, in the introductory paragraph, that the coloring of the eyes 

 of this species, in living specimens, differs from the type of coloring which prevails in 

 the genus Chrysops. The anal cell is broadly open in most specimens ; in one of mine, 

 however, it is closed. 



