Genus Andrenayounc? in New Mexico. 87 



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

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

 number. 



Although mexicanorum falls in the same artificial section 

 Sisfi-acta, it really has nothing to do with that insect, but is 

 very closely related to asdepiadis. 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) distinguislied by the truncate 

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

 enclosure of metathorax, narrow elongate male abdomen, 

 short antennas in both sexes, and the considerable amount of 

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

 jointed, the glossa pointed at tip. I have also three smaller 

 sj^ecies, which are congeneric but do not have the wings 

 conspicuously clouded at the apex. 



y. Wings not conspicuously clouriied at apex. 



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



Andrena platyparia^ E,ob,, race occidentalism Ckll., n. race. 



(J. 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 

 throughout dirty whitish, thin but quite long, slightly tinged 

 with ochraceous on dorsum. Mesothorax dullish, micro- 

 scojjically tessellate, with shallow sparse punctures ; scutellum 

 much more shining, with only a few scattered punctures. 

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

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

 "Wings smoky hyaline, tinged brownish ; nervures and stigma 

 brown. Abdomen niicroscopically tessellate, with hardly 



