Studies of North American Bees 73 



an A, patch involving ocelli, head behind, propleura, narrow anterior 

 and posterior margins and median line on mesoscutum, depressed areas 

 under wings and on sides of mesoscutellum and metanotum, coxae behind, 

 metapleura and propodeum except large yellow-spotted red areas on the 

 sides of the posterior face of the propodeum, which do not encroach on 

 enclosure, all black. Antennae, except scape in front, wholly red. joint 

 3 heavy, slightly exceeding 4. Wings subhyaline, faintly apically clouded, 

 nervures and stigma pale red, basal nervure distinctly basad of trans- 

 verso-medial nervure. Legs, except for the yellow marks mentioned and 

 slight dark lines on the posterior femora behind, bright red, the tibiae out- 

 wardly tuberculate and armed apically with three large stout strongly 

 recurved setae, the hair on hind basitarsi within pale golden. Head and 

 thorax coarsely and closely but shallowly punctured, abdomen minutely 

 reticulate. Hair all white, very thin and inconspicuous except on face, 

 cheeks, lower pleura, mesoscutellum and metanotum, and propodeum, 

 where it is fairly copious and longer. 



Material. — Ute creek, Costilla county, Colorado, 9,000 feet, 

 June 27, 1907 (L. Bruner), 5- 



N. alpha is most closely allied to the morrisoni-fiagcUaris-crazv^ 

 fordi-elrodi-obliterata-etc. group of females, but differs from 

 all of them except flagcUaris in the heavy third antennal joint 

 which is longer than the fourth. Thus, as Cockerell states, the 

 proportion of the antennal joints would run it in Robertson's 

 table to Holonomada while its very close relatives belong to 

 Heininoinada (=Xanthidiuni), and the male is unquestionably 

 an Heminomada; obviously, this is one of the points where the 

 two subgenera merge more or less. The species is close to A'^. 

 morrisoni Cresson, but further differs in smaller size (niorrisoni 

 is lo-ii mm. long), in having tergite i red with its band reduced 

 to narrow lateral spots, and the bands on tergites 2 and 3 much 

 narrowed or wholly interrupted by the encroachments of the 

 broad red bands on the apical margins and large red medio-basa1 

 areas (in morrisoni the tergites have complete broad yellow 

 bands, that on tergite i being usually more or less deeply notched 

 on the anterior middle, but those on 2 and 3 of uniform width 

 and not narrowed by the encroachments of the narrowly reddish 

 apical margins or by red medio-basal areas), in the red or mostly 

 red propodeal spots (these yellow margined by red in morrisoni) , 

 and in the almost wholly red mesoscutum (morrisoni has the 



73 



