Genus AjidLxexm found in New Mexico. 87 



dusky, hardlj at all ferruginous, the stigma black. The 

 teeth on the hind tibiae are better developed, about twenty in 

 number. 



Although mexicanorum falls in the same artificial section 

 ^sfracta, it really has nothing to do with that insect, but is 

 very closely related to asclepiadis. I was at first inclined to 

 regard these allied forms as sexes of one species, but they 

 come from different localities and the clear ferruginous stigma 

 of mexicanorum is distinctive. Yet I suppose they are rather 

 geographical races than distinct species, and intermediates 

 may be looked for in the Rio Grande Valley between Juarez 

 and Albuquerque. 



These two bees are not true Andrena, but will fall in a 

 new group (genus or subgenus) distinguished by the truncate 

 marginal cell, crenate-dentate hind tibias of male, pubescent 

 enclosure of metatiiorax, narrow elongate male abdomen, 

 short antennae in both sexes, and the considerable amount of 

 yellow on face even in female. The maxillary palpi are six- 

 jointedj the glossa pointed at tip. I have also three smaller 

 species, which are congeneric but do not have the win«s 

 conspicuously clouded at the apex. 



y. Wings not conspicuously clouded at apex. 



i. Head very large ; hind margins of cheeks strongly keeled. 



Andrena platyparia^ Rob,, race occidentalism Ckll., n. race. 



^ . Length about 9 millim. Differs from platyparia by 

 the flagellum being wholly black, the legs very dark brown, 

 so as to seem black except the paler tarsi, the abdomen 

 piceous, margins of the segments narrowly testaceous. The 

 first joint of the flagellum is not so long as the second and 

 third together. Clypeal punctures sparse but distinct. Basal 

 process of labrum projecting, rounded. Mandibles toothed 

 within. Front conspicuously longitudinally striate. Vertex 

 microscopically tessellate. Cheeks with a very strong keel 

 behind, curving over to the apex of the orbits. Pubescence 

 thi'oughout dirty whitish, thin but quite long, slightly tinged 

 with ochraceous on dorsum. Mesothorax dullish, micro- 

 scopically tessellate, with shallow sparse punctures ; scutellura 

 much more shining, with only a few scattered punctures. 

 Enclosure of metatiiorax ill-defined, dull and granular, with 

 a row of short wrinkles along base. Tegulge dark testaceous. 

 "Wings smoky hyaline, tinged brownish ; nervures and stigma 

 brown. Abdomen microscopically tessellate, with hardly 



