OSTEN SACKEN ON WESTERN DIPTERA. 341 



preceding (as far as I can judge from the description), but the female is 

 larger, face altogether beset with ochraceous pollen, except on the tuber- 

 cle and on the cheeks; the brownish mark on the tubercle is Y-shaped; 

 in the male, the front is black, shining above the antennae only, pollinose 

 along the eyes. Abdomen of a pure bronze-color, densely beset with 

 golden-yellow pile in the female; somewhat darker in the male; the 

 velvet-black hind margins of segments 2 and 3 are subinterrupted 

 in the female, and somewhat broader in the male. Legs of the female 

 of a saturate reddish-yellow, the penultimate tarsal joint slightly infus- 

 cated; in the male, the tips of the tarsi are infuscated and the four 

 anterior femora have a brown spot on the front side. Wings yellowish- 

 hyaline on the antero-proximai portion, grayish-hyaline along the pos- 

 terior margin; costal cell yellow; stigma saturate-yellow; a brown 

 cloud, in the shape of a short cross-band, between the root of the third 

 vein and the cross-vein at the base of the last posterior cell ; small cross- 

 vein likewise clouded with brown (the* coloring of the wing is more 

 intense in the female than in the male). Seems to be very variable in 

 size ; one of the males is about 10 ram long, the other 8 mm ; the female 

 nearly 12 mm . 

 Hal). — Kentucky (F. G. Sanborn). Two males and one female. 



3. Ghrysochlamys nigripes u. sp. — Male and female. — General color- 

 ing much duller than in Chr. dives, metallic blackish-green ; pollen on 

 the face and front dull yellowish ; frontal pollinose cross-band ( 9 ) much 

 narrower, and hence the black, shining space above the antennae 

 larger. The prevailing pubescence on thorax and scutellum is black ; 

 black, opaque hind margins of the segments 2 and 3 in the male only, 

 not in the female. Femora brown, except the tip ; tibiae brownish - 

 yellow, more or less infuscated before the tip, especially the front pair ; 

 tarsi brownish-red at base, brown at tip. Wings grayish-hyaline, feebly 

 tinged with brownish-yellow at the root and on the stigma; costal cell 

 subhyaline in the female; brownish clouds on cross- veins very weak. 

 Length about 9 mm . 



Hab. — Massachusetts (F. G. Sanborn). A male and a female on the 

 same pin. 



4. Ghrysochlamys crcestjs.— Male.— Very like 0. dives, but differs in 

 the arista being black and the hind margins of the abdominal segments 

 2 and 3 without velvet-black hind borders. The brown spot on the 

 facial tubercle is of an indefinite outline, not Y-shaped, as in the two 

 preceding species. Antennae reddish-brown, very little darker along 

 the upper edge. Abdomen uniformly of a bright bronze-green, thickly 

 beset with golden-yellow pile. Legs altogether of a saturate reddish - 

 yellow. Length 10-ll mm , but much broader than the male of 0. dives o 1 * 

 the same size. 



Hob.— Near Salt Lake City, Utah (Mr. Barfoot). 

 Sphecomyia brevicornis n. sp. — Male.— Antennae black, about half 

 as long as the eye from its upper to its lower corner; they are inserted 



