-We review the literature on phylogeny, fossil record, biogeography, and social evolution in Halictidae. We then present a phylogenetic analysis of tribal, generic, and subgeneric relationships within the subfamily Halictinae using a combined data set of three nuclear genes: long-wavelength (LW) opsin, wingless, and EF-1α. The data set includes 89 species in 34 genera representing all four halictid subfamilies, and all tribes of the subfamily Halictinae. Our study provides several new insights into the phylogeny of the African Halictinae. First, our results support a close relationship between Mexalictus (a small genus of bees occurring at high elevations in the mountains of western North and Central America) and the African/Asian genus Patellapis. Second, our results support placement of the parasitic genus Parathrincostoma well within its host genus Thrinchostoma, suggesting that Parathrincostoma should be treated as a subgenus of Thrinchostoma. Finally, our data set provides strong support for the monophyly of Patellapis (sensu Michener, 2000) and establishes monophyletic groups within the African subgenera that could be the basis for future taxonomic studies.evolution / biogeography / bees / Apoidea