1896.] NATUKAL SCIENCES OF PHILADELPHIA. 61 



black bands. Venter orange, immaculate. Quite as often, perhaps 

 more frequently, the abdomen is shining black above, except the 

 terminal segment which is testaceous, and the more or less obviously 

 testaceous distal margins of the other seo:ments. 



9 . — Somewhat larger ; head rounder, not broader than thorax. 

 Punctures of mesothorax distinct but scattered. The pale markings 

 all yellowish-white instead of yellow. Face dark, clypeus black 

 contrasting with the green upper part of face. An irregularly 

 triangular yellowish-white patch on each lower corner of face 

 between clypeus and orbit. Coxje black, their ends whitish. Femora 

 black, their tips whitish. Tibise whitish, middle and hind tibise 

 largely suffused with black. Dorsum of abdomen with the black 

 nearly covering the segments, leaving transverse white areas or 

 bands, not continued to lateral margin, on segments 2-4. Venter 

 whitish, not banded. 



Hab. — Santa Fe, N. M., close to the Denver & Rio Grande depot, 

 at flowers of 3Ienzelia nuda, Aug. 3, 1895, many specimens. They 

 were associated with Bomhus (abundant) and Andrena (rare). 



13. Perdita pallidior n. sp. 



S . — Resembles the $ of mentzelice, but differs in the cheeks being 

 unarmed beneath, in the smaller head, the second submarginal cell 

 more narrowed above, the legs entirely yellow, the abdomen above 

 orange-yellow, with the first segment nearly all dark brown or 

 black, and a dark brown band on segments 2 and 3, that on 3d fail- 

 ing some distance before the lateral margin. 



9 . — Resembles the 9 of mentzelice, but differs in the legs being 

 all yellowish-white, except a dusky shade on inside of anterior 

 femora, and outside of middle and posterior tibise. The white sub- 

 triangular marks on sides of face are rather more produced upward 

 along the orbital margin. The abdomen above is yellowish-white, 

 the first segment with a broad brown-black ring, the second and 

 third segments with dark bauds, the fourth segment with a pair of 

 dark spots, suffused in outline. 



Hab. — Albuquerque, N. M., close to Prof. Hadley's house, abun- 

 dant on flowers of Mentzelia nuda, Aug. 15, 1895. A single 9 was 

 also swept from Gutierrezia sarothrce (det. E. O. Wooton) at the 

 same time and place. No other bees were then found upon the 

 Mentzelia, except Perdita pulchrior. On the G^ltierrezia were found 

 also Perdita gidierrezice and P. austini, one each. 



