Ashmeadiella Cockerell (Megachilidae: Osmiini) is a bee genus endemic to North America, with greatest richness in arid and Mediterranean regions of the southwestern United States. Species relationships of Ashmeadiella were last analyzed in the 1950s, when Robert Sokal and Charles Michener developed a novel statistical clustering method for classification called numerical taxonomy. To revisit the taxonomic groups they established, we built a molecular phylogeny including all five subgenera. Furthermore, we assembled life history data to lay the foundation for future conservation programs for these bees. We chose three aspects of bee biology that can inform conservation strategies: documenting periods of the year adult bees are flying, assembling data for the flowers each species visits, and compiling the localities and ecoregions where each species is reported. Our results suggest that some Ashmeadiella species may need to be synonymized and that the subgenera should be revised due to non-monophyly. We therefore propose synonymizing the subgenera Cubitognatha and Chilosima with Arogochila. Biological data from published collection records reveal that adult flight periods range from a few months to 11 mo; most species utilize floral resources from multiple plant families; and, over half of the species have ranges extending into the Mojave Desert.