lOO JoiRNAJ, Nkw York Ent. Soc, [Vol. ii. 



like the bristles of the last two, black. First joint of antenna- slender, much shor- 

 ter than the head, but slightly wider than the second ; third joint of nearly the 

 same width and length as the first, tapering but slightly toward the apex; style one- 

 sixth as long as the third joint. Thorax opaque, grayish-black pollinose, a darker 

 median vitta, two vittne and the lateral margins light gray. Abdomen opaque, 

 brownish-black pollinose except the first segment and hind and lateral margins of 

 the others, which are gray. Wings whitish hyaline, the stigma and a broad border 

 to the veins, brown; fourth posterior cell closed. All femora provided with 

 bristles. 



Q — Same as the cT ^^''^h these exceptions: Front near its middle marked with 

 a transverse p-iir of transversely oval polished spots; no black pile on sides of face; 

 seventh and following abdominal segments shining. Length, lo mm. 



Colorado and California. Types in National Museum. 

 This species would fall in With Jo/iiiso/ii in my table, but in the 

 latter the third joint of the antenna is only three-fourths as long 

 as the first, the thorax is yellowish and gray pollinose, the abdomen 

 on the first si.x segments uniformly gray pollinose, etc. 



Thereva diversa, sp. nov. 



9 — Black, the second joint of antenna.' and base of the third, the palpi, 

 femora, tibire, base of tarsi, venter (largely) and broad hind margin of each abdo- 

 minal segment except the first, yellowish; on the second segment this color occupies 

 the last third and the lateral margins, the sixth and following segments are almost 

 wholly yellowish. Head opaque, gray pollinose, a polished black spot in middle of 

 front, separated from the eyes by pollen that in certain lights appears velvet-black; 

 the polished spot is produced upward at its middle but is widely separated from the 

 lowest ocellus; pile of front and of fourth and following abdominal segments 

 largely black, that on the face, cheeks, occiput, thorax, scutellum and first three 

 abdominal segments largely yellowish. First joint of antenna; scarcely wider than 

 the second, the third equal in width and length with the first, tapering but slightly 

 toward the apex; style one-sixth as long as the third joint. Thorax opaque, gray- 

 ish-black pollinose, a median, pure black vitta, also two light-gray vittn:;, the lateral 

 margins of this same color; bristles of thorax and scutellum black. Abdomen, 

 except the first segment, polished. Wings grayish-hyaline, stigma pale brown> 

 veins narrowly bordered with brownish. 



cS differs from the 9 ^s follows: Femora, except sometimes the apex, black; 

 front destitute of a polished spot; pile of face sometimes partly black; abdomen 

 sub-opaque, the yellow color less extended. Length, 9 to ii mm. 



C'olorado, Montana and Florida. Four males and two females, 

 from Dr. Riley's collection. 



There appears to be no doubt that the two se.xes here described 

 belong together; the Colorado examples, two males and as many 

 females, each bear the same kind of a label, and are pinned lower 

 down than usual, indicating that they were taken by the same 

 collector. In my table, the female would fall in with y/t/r/V/V/rA?, 

 in which the polished frontal spot extends to the lowest ocellus and 



