AbstractBackgroundSweat bees of the genusAgapostemonGuérin-Méneville, 1844 (Hymenoptera:Halictidae) are common and widespread in the Americas. Despite distinct morphological characters that were recognised in earlier taxonomic treatments,AgapostemonfasciatusCrawford, 1901 has been considered a variety ofA.melliventrisCresson, 1874 since the 1930s and later placed into synonymy underA.melliventrisin the early 1970s.New informationA more detailed study of morphology (including examination of type materials), distribution and genetic data (i.e. DNA barcodes) of these two taxa suggests they are not conspecific. As such,A.fasciatusis resurrected as a valid North American bee species.Agapostemonfasciatusranges further north in North America thanA.mellivenrtis, reaching the southern Prairies Ecozone of Canada (Alberta, Saskatchewan), while most records ofA.melliventrisare from the south-western United States and northern Mexico. More accurate distributions for both species can be modelled as specimens in collections are identified using the diagnostic features provided. However, additional work is required on theA.melliventrisspecies complex in the southern United States as genetic data suggest that multiple taxa could be present.