The Andrenidae are a large, nearly cosmopolitan (absent in Australia), nonparasitic bee family, with most of the diversity in temperate and/or arid areas (warm temperate xeric). It includes some enormous genera (e.g., Andrena with over 1300 species, and Perdita with nearly 800). One of the subfamilies, Oxaeinae, is so different in appearance that they were typically accorded family status, but careful phylogenetic analysis reveals them to be an offshoot within the Andrenidae, very close to the...