| The bee subgenus Dialictus (Hymenoptera: Halictidae: Lasioglossum) are the most commonly collected bees in North America and have the most diverse social systems of any equivalent group of insects. Despite their importance, as pollinators and as model organisms for studying the evolution of social behaviour, Dialictus remain one of the greatest challenges in bee taxonomy. A taxonomic revision of the metallic species of Canadian Dialictus has been completed which resolves many of the difficulties of these bees. Complete species descriptions with illustrations are provided for each species along with keys to identify males and females of all metallic Lasioglossum in Canada.;Fifty new synonymies are proposed.;Three new combinations are applied: L. (D.) leucocomum (Lovell), L. (D.) oceanicum (Cockerell) and L. (D.) planatum (Lovell).;The species L. (D.) atriventre (Crawford) is considered a nomen dubium.;The following sixteen new species are described: Lasioglossum (Dialictus) abundipunctum new species; L. (D.) atwoodi new species; L. (D.) ebmerellum new species; L. (D.) ephialtum new species; L. (D.) imbrex new species; L. (D.) knereri new species; L. (D.) macroprosopum new species; L. (D.) packeri new species; L. (D.) prasinogaster new species; L. (D.) reasbeckae new species; L. (D.) sablense new species; L. (D.) sandhousiellum new species; L. (D.) sheffieldi new species; L. (D.) sitocleptum new species; L. (D.) timothyi new species; L. (D.) yukonae Gibbs, new species.;The following ten new records for Canada are reported: L. (D.) achilleae (Mitchell), L. (D.) brunneiventre (Crawford), L. (D.) callidum (Sandhouse), L. (D.) incompletum (Crawford), L. (D.) hudsoniellum (Cockerell), L. (D.) marinense (Michener), L. (D.) pacatum (Sandhouse), L. (D.) pallidellum (Ellis), L. (D). sagax (Sandhouse); L. (E.) testaceum (Robertson), and L. (D.) zophops (Ellis). The Canadian records of two species, L. (D.) disparile (Cresson) and L. (D.) ceanothi (Mitchell), do not seem reliable and these species are not included in the revision.;Two species, L. testaceum (Robertson) and L. rufulipes (Cockerell), are transferred from the subgenus Dialictus to Evylaeus.;Key words. Dialictus, Lasioglossum, Halictidae, new species, DNA barcoding, taxonomy, Hymenoptera, sweat bee... |
