Studies of North American Bees 29 



Abdominal tergites 1-5 with pale whitish yellow bands, that on tergite i 

 somewhat narrowed medially and laterally slightly notched on anterior 

 margin, that on 2 broad laterally and gradually much narrowed medially, 

 that on 3 broadly interrupted and usually reduced to elongate lateral spots, 

 those on 4 and S complete and of subuniform width, their anterior margins 

 wavy. Venter black, sternite 3 with a broad, complete, pale whitish yellow 

 band, sternite 4 with a narrow, medially interrupted band with the ends of 

 the lateral halves swollen, or sometimes only these swollen ends persisting 

 as four or two spots. Anterior coxae not spined. Legs dark red, varied 

 with pale yellow as described, the coxae basally and below and the hind 

 tibiae and tarsi externally, black. Clypeus shining, finely and sparsely 

 punctured, face coarsely but very weakly punctured, vertex and meso- 

 scutum finely and densely, subcancellately punctured. Antennae red, suf- 

 fused with blackish above, joint 3 distinctly exceeding 4. Wings sub- 

 hyaline, broadly fuliginous along costal and upper apical margin, a clear 

 area in and beyond third submarginal cell. Second submarginal cell mod- 

 erately narrowed above, receiving the first recurrent nervure slightly 

 beyond the middle, the nervures black, stigma dark brown. Pubescence 

 very short, thin and sparse, most noticeable between antennae and on 

 mesopleura, the propodeum except enclosure with rather dense, appressed, 

 sericeous hair, the inner sides of hind basitarsi copiously short-haired, all 

 the pubescence whitish. 



c?. Length 6-7.5 mm. Like the $, but extreme sides of labrum, inferior 

 orbits, larger lateral face marks covering lower corners of face, clypeus 

 except broad sutural margins separating it from lateral face marks, and 

 sometimes a small supraclypeal spot, pale whitish yellow. Coxae mostly 

 black, hind femora behind suffused with blackish. Sixth abdominal tergite 

 with a pale yellowish band, band on sternite 3 sometimes medially inter- 

 rupted, apex deeply notched. 



Type. — Tucson, Arizona (F. H. Snov\^, No. 2465), $• 



Allotype. — Type locality (F. H. Snow), J*. 



Paratypes. — Type locality (F. H. Snow), n $, 5 cJ*. 



This species has all the appearance of Micronomada, and is 

 in fact most closely related to A^. texana Cresson and its allies, 

 but the coxal spines are lacking. In this respect it resembles N. 

 wheeleri Ckll. and its subspecies N . w. engelmanniae Ckll. which 

 belong to the belfragei group of Micronomada, but are also 

 aberi-ant in the lack of spines on the anterior coxae. From 

 wheeleri and engelmanniae this species may be known at a glance 

 in the $ by the wholly black mesoscutum, while from engel- 

 manniae (^ it differs in the entirely different yellow marks on 



183 



