Studies of North American Bees 17 



entirely black, or sometimes with small yellow spots, its lobes broadly 

 and evenly rounded, semicircular. Legs with a yellow stripe on outer face 

 of tibiae and whole of outer face of basitarsi yellow, the tibial stripe some- 

 times obliterated apically. Apical tarsal joints dark. In other characters 

 as in the $. 



?. Length 8-9 mm. Entire face coarsely and very densely punctured, 

 subcancellate on clypeus but separated and distinct on vertex, bearing long 

 thin white hair which becomes dense in a tuft about each antennal base 

 and on scape. Antennae wholly black, the scape conspicuously punctured, 

 joint 3 slightly exceeding 4. Clypeus with its apical margin depressed, 

 slightly sinuate, bidentate at each side, the inner tooth the larger. Cheeks 

 coarsely and closely but very shallowly punctured, sparsely white hairy. 

 A small yellow spot on vertex behind superior apex of eye. Entire thorax 

 very coarsely and closely punctured, the vertex and thorax above with 

 dense erect deep brownish ochreous hair, the pleura and legs with copious 

 grayish white hair. Margins of tegulae broadly yellow, the central area 

 brownish black, and wing bases with a yellow spot. Tubercles yellow, 

 Mesoscutellum with four yellow spots arranged in an arc, the inner pair 

 of spots twice as large as the outer pair. Legs black except for a broad 

 yellow stripe on the anterior face of all of the tibiae, and sometimes a 

 small yellow stripe on the outer face of the hind basitarsi. Inner face of 

 tarsal joints with blackish hair, the outer surface largely fuscous and 

 black but considerably intermixed with silvery hairs on the bases of the 

 basitarsi. Ventral scopa usually pale golden brownish more or less mixed 

 with blackish, sometimes wholly black. Abdominal tergites distinctly 

 punctured, tergites 1-6 with broad yellow bands, narrowly interrupted 

 medially, those on tergites 2-6 emarginate in the middle of each lateral 

 half anteriorly. Sides and disk of abdomen with sparse erect pale hair. 

 Wings very slightly darkened apically, nervures and stigma black. 



Type. — Bad Lands at mouth of Monroe canyon, Sioux county, 

 Nebraska, June 6, 1901, on Homalobus tenellus (M. Gary), (^. 



Allotype. — Type lot, $. 



Paratypes. — Type lot, 7 ?, i c^; type locality, May 28, 1901, on 

 Homalobus tenellus (L. Bruner), 4 $; do. (M. A. Carriker), 

 I c^; Warbonnet canyon, Sioux county. May 28, 1901, on Astra- 

 galus hypoglottis (M. Gary), i ?, i c^; do., June 16, 1901, on 

 Astragalus hypoglottis (M. Gary), i $ i c^; Ute creek, Costilla 

 county, Colorado, 9,000 feet, July 3, 1907 (L. Bruner), i $• 



From A. tenui florae Gkll., this species is easily know^n by the 

 spotted mesoscutellum and yellow tubercles in the female and by 

 the spotted mesoscutellum and broad yellow stripe on the front of 



17 



