Abstract Argentina is the country with the second highest number of bee species in the Neotropics after Brazil. Fifteen new records of wild bees belonging to genera of the families Apidae, Andrenidae, Colletidae, Halictidae, and Megachilidae are presented. Species of genera Callonychium Brèthes (Andrenidae), Gaesischia Michener, LaBerge & Moure, Melitoma Lepeletier & Serville, Trichocerapis Cockerell (Apidae), Hylaeus Fabricius (Colletidae), Habralictus Moure, Megalopta Smith, Neocorynura Schrottky, Pseudaugochlora Michener, Rhectomia Moure, Thectochlora Moure (Halictidae), and Bothranthidium Moure (Megachilidae) are recorded for the first time for Argentina. Whereas the genera Trichocerapis, Megalopta, Rhectomia, and Bothranthidium are cited for the first time in the country. Brazil Apidae Andrenidae Colletidae Halictidae presented , (Andrenidae) Michener Serville (Apidae) (Colletidae) Smith Schrottky (Halictidae) (Megachilidae (Andrenidae (Apidae (Colletidae (Halictidae

Abstract Gynandromorphs are individuals that display both male and female features throughout the body and are rarely found in nature. We document and describe two new gynandromorphs of the large carpenter bee Xylocopa (Neoxylocopa) augusti reared from a trap-nest in La Plata, Buenos Aires, Argentina. In addition, based on a literature review, we assessed the frequency of the different types of gynandromorphs, and the body part affected, among large carpenter bees. Both gynandromorphs were assigned to the mixed category, the most common category reported in the literature (22 of 25 specimens). The remaining three specimens exhibit a bilateral pattern in all tagmata. The presence of both sexes’ secondary sexual characteristics occurred more frequently on the mesosoma than on the head or metasoma. Trap nests used in bee hotels promote the conservation and study of wild bees and might facilitate the discovery of rare cases of gynandromorphs that would remain unknown otherwise under normal nesting conditions in the wild.