CAMERON. SOME ODYNEWNAE OF THE SOUTHWESTERN UNITED STATES 129 



the top half of the sides of metanotum, an obhque conical mark below the 

 tegulae, lines on the apices of the abdominal segments, an oblique mark touch- 

 ing the apical line on the sides of the first about three times longer than wide, 

 a large irregular oval spot on the sides of the second, and two small spots in 

 the center of the second ventral, pale yellow. Legs pale yellow, the coxae, 

 trochanters and base of femora black above, the black on the fore-femora on 

 the basal third, on the intermediate reaching shortly beyond the middle, on the 

 hinder close to the apex ; the tarsi tinged with fulvous. Wings hyaline, tinged 

 with violaceous, the nervures and stigma black. Male — Length 6-7 mm. 

 Fedor, Texas. (Birkmann.) 



Antennae stout, becoming thicker towards the apex, the hook brown, 

 reaching to the middle of the penultimate joint. Clypeus slightly longer than 

 wide, the lower half straight, obliquely narrowed, the apex with a shallow 

 rounded incision. Base of thorax almost transverse, the sides not projecting. 

 Apex of postscutellum broadly rounded. Sides of metanotum rounded, not 

 margined. Basal slope of first abdominal segment smooth, the second segment 

 a little wider at the apex than it is long; the apex is more strongly punctured 

 than the rest; it is slightly reflexed. The apical half of the middle femora is 

 dilated laterally and compressed, of irregular form. Puncturation of the head 

 and thorax close and strong; they are covered with white pubescence. 



This species is based on three males which agree in form, sculpture, size, 

 and coloration, and in having the middle femora more or less dilated and com- 

 pressed. The structure of the middle femora is not quite alike in any two of 

 them, though this may not be a point of specific distinction. The two ventral 

 yellow marks may be absent. 



Odynerus mediatus n. sp. 



Male — Length 6 mm. Three Rivers, California (Culbertson.) 

 This species agrees in coloration of the body with O. appro.rimatus, hav- 

 ing also the same form of clypeus and thorax ; they may be separated as fol- 

 lows : 



A. Hind femora black except at the extreme apex, the middle femora as 

 as seen from the front dilated from near the middle, the apex 

 of the expanded part dilated, with an oblique slope ; the middle 

 tibiae becoming gradually widened from the base to the apex ; 

 the second abdominal segment distinctly longer than wide, its 

 apex flat, its basal half smooth ; the apical weakly punctured ex- 

 cept at the apex, where the puncturation is stronger. 



approximatus. 



AA. Hind femora yellow on the outer side, black below and within, middle 



femora compressed at the apex, clearly thinner than the basal. 



the middle tibiae not much thickened at the apex compared with 



the base, the second segment distinctly punctured throughout, its 



apex reflexed. mediatus. 



The yellow on the legs (especially on the anterior) is largely sufTused with 



rnfo-fulvous; the pubescence is dense, white, and silky; the sides of the first 



