NO. 1852. BEES OF THE GENUS NOMADA—COCEERELL. 243 



finel}" pubescent; apical plate strongly notched; venter yellow, with 

 broad black bands at bases of second and fourth segments. 



Habitat. — Arizona, from the Baker collection, wi£h No. 1856. 



Type.— Cat. No. 14024, U.S.N.M. 



Distinguished among male Xanthidium by the red markings on the 

 mesothorax. In the table of Rocky Mountain species it runs to N. 

 perivincta Cockerell, the male of which is unknown, but from analogy 

 with other species it is practically certain that it is not the male of 

 perivincta. There is evident relationship with N. elrodi Cockerell, but 

 that species differs by the broader face, black postscutellum, etc. 



NOMADA OSBORNI, new species. 



Male.— Length, about 6 mm. ; head and thorax black, quite densely 

 clothed with entirely white hair ; mesothorax with large strong punc- 

 tures, the shining surface between them conspicuous on the disk; 

 scutellum very flat; eyes pale olive-green; facial quadrangle longer 

 than broad; face densely covered wdth white hair; mandibles simple, 

 yellow with the apical part ferruginous; broad band beneath eyes, 

 labrum, lower half of cl^^peus (\vith an upwardl}^ directed angle in 

 middle), and narrow lateral face-marks (ending in a very sharp point 

 at about level of antennae), all yellow; scape not much swollen, 

 broadly yellow in front; flagellum bright ferruginous, nearly the 

 basal half infuscated above; third antennal joint conspicuously shorter 

 than fourth; tubercles and a small mark on lower part of pleura, 

 almost hidden by hair, yellow, thorax otherwise black; tegulae pale 

 yellowish with a darker spot; wings a little smoky, darker at apex; 

 stigma dark ferruginous, nervures fuscous; b. n. going just basad of 

 t. m.; second s. m. receiving first r. n. in middle; third s. m. nearly as 

 broad above as second ; anterior legs light ferruginous, the tibise dark 

 behmd, and yellowish apically in front; middle and hind legs darker, 

 strongly infuscated behind, the knees and apices of tibiae yellow; hind 

 tibise with much white hair behind; abdomen long and tapering, 

 broadest at second segment, bright chestnut red, with very obscure 

 small yellowish spots at sides of second and third segments; a broad 

 yellow band on sixth segment, not reaching sides ; first segment dark 

 at base, and dusky on apical margin; broad apical margins of segments 

 very thinly clothed with white hair; apical plate notched; venter 

 red, the first segment with a cordiform black mark, at the end of 

 which is a patch of white hair; apical ventral tuft of white hair small. 



Habitat. — Tucson, Arizona (H. Osborn) . 



Type.— Cat. No. 14025, U.S.N.M. 



A Nomada s. str., related to N. vexator Cockerell, but smaller, with 

 differently colored tegulas, the darker abdomen with much less yellow, 

 etc. In the table of Rocky Mountain Nomada it runs to 66, and goes 

 with N. vexator in a new division. The dorsum of thorax shining 

 between the punctures, and the flattened scutellum, are highly 

 distinctive. 



