A revision of the bees of the genus Andrena of the Western Hemisphere. Part 8. Subgenera Thrsandrena, Dasrandrena. Psammandrena. Rhacandrena, Euandrena, Oxyandrena. Transactions Am. ent. Soc, 103(1) 1977: 1-143.illust.. 43 [Zoological Record Volume 114]