A problematic species complex for Lasioglossum subgeneric diagnostics in North America (Hymenoptera: Halictidae) Author Hettiarachchi, Thilina 0000-0003-4430-4105 Department of Entomology, University of Manitoba, 12 Dafoe Rd. Winnipeg, MB, R 3 T 2 N 2, Canada. hettiart@myumanitoba.ca Author Gibbs, Jason Department of Entomology, University of Manitoba, 12 Dafoe Rd. Winnipeg, MB, R 3 T 2 N 2, Canada. text Zootaxa 2024 2024-01-25 5404 1 206 235 https://www.mapress.com/zt/article/download/zootaxa.5404.1.13/52776 journal article 10.11646/zootaxa.5404.1.13 1175-5326 10566480 A902495B-8A81-4F33-BA18-B8E3E79FA6A9 Key to Lasioglossum subgenera in North America Modified from McGinley (1986) , Michener (2007) , and Gibbs et al . (2013) . 1. Second submarginal crossvein (1rs-m) as strong as first (second abscissa of Rs) ( Fig. 16A ), difficult to see in male; head and mesosoma black, except L. pavonotus (Cockerell) ; male clypeus often flat or depressed ventrally; flagellomere 2 subequal to pedicel and flagellomere 1 combined ( Fig. 17A ); body length usually greater (approx. 7–12 mm )..................... 2 - Second submarginal crossvein (1rs-m) weaker than first (second abscissa of Rs) ( Fig. 16B ), at least in female; head and mesosoma variable in colour; male clypeus often rounded; flagellomere variable, if black and moderately large (> 6 mm ), then flagellomere 2 longer than pedicel and flagellomere 1 combined ( Fig. 17B )....................................... 3 2. Propodeum with lateral carina well developed, reaching dorsal surface ( Fig. 18A ); dorsal surface coarsely sculptured, shorter than scutellum ( Fig. 18A ); T1 without basal hair band ( Fig. 18A ); head long (length/width ratio = 0.88–1.0) ( Fig. 19A ); male gonostylus without retrorse lobe ( Fig. 20A )................................................... L. ( Leuchalictus ) - Propodeum with lateral carina usually poorly developed, not reaching dorsal surface ( Fig. 18B ), but if strong ( Figs. 18C, 18D ) then dorsal surface longer than scutellum ( Fig. 18C ) or weakly sculptured ( Fig. 18C ) or T1 with basal hair band or head short ( Fig. 18D ) (length/width ratio = 0.77–0.89) ( Fig. 19B ); male gonostylus with retrorse lobe ( Fig. 20B ).... L. ( Lasioglossum ) 3(1). Head and mesosoma distinctly metallic (green, blue, or golden)................................................ 4 - Head and mesosoma black-brown, at most with weak reflections............................................... 6 4. Head and mesosoma brilliant metallic (Antillean, southern Florida ); male inner metatibial spur typically pectinate; male gonostylus without retrorse lobe........................................................... L. ( Habralictellus ) - Head and mesosoma dull metallic; male inner metatibial spur ciliate; male gonostylus with retrorse lobe................ 5 5. Body size usually small ( 3.5–6 mm ); female T1 usually with appressed hairs at least laterally ( Fig. 21A ) in North American species (except L. ruidosense and L. petrellum (Cockerell) species complexes, L. microlepoides (Ellis) , L. pavoninum (Ellis)) , typically lacking erect hairs medially; female mandible almost always with small preapical tooth ( Fig. 21B ), except in the wood-nesting L. coeruleum (Robertson)) (cosmopolitan)............................................ L. ( Dialictus ) - Body size usually larger ( 6–8 mm ); female T1 without appressed hairs, medially with distinct erect hairs ( Fig. 22A ); female mandible often strongly bidentate ( Fig. 22B ), if preapical tooth small, then propodeum with distinct lateral carina reaching dorsal margin (primarily from Panama to Mexico , except L. aquilae , which reaches to high elevation areas in the southwestern USA )................................................................................ L. ( Eickwortia s.l. ) 6 (3). Head wide ( Fig. 23A ); female inner metatibial spur with fine oblique teeth, not as tall as width of main rachis ( Fig. 23A ); male gonostylus without retrorse lobe; metasomal sterna with erect pubescence.............................. L. ( Evylaeus ) - Head usually longer ( Fig. 23B ); female inner metatibial spur usually with longer, narrow or fat teeth, often taller than width of main rachis basally ( Fig. 24B ); male gonostylus with retrorse lobe; metasomal sterna with variable pubescence.......... 7 7. Foretibia of female with long projection ( Fig. 25A ); metapostnotum enclosed by carina, with distinct parallel carinulae ( Fig. 26A ); frons with two bulbous protuberances ( Fig. 26B ); retrorse lobe absent (Neotropical)....................................................................... L. gattaca complex ( L. gattaca and L. hartmanni Danforth and Wcislo ) - Foretibia of female without long projection ( Fig. 25B ); metapostnotum not as above; retrorse lobe present (widespread)... 8 8. Female mandible strongly bidentate ( Fig. 27 ), subapical tooth nearly equal to apical one; male metasoma with entirely paleorange sterna; gonobase at middorsum less than one-fourth length of gonocoxite; T1 narrow or apex of clypeus distinctly thick ( Mexico and Central America)........................................................... L. ( Eickwortia s.s. ) - Female mandible with small preapical tooth dorsally; male gonobase at middorsum usually more than one-third length of gonocoxite.......................................................................................... 9 9. Either propodeum with weak lateral carina and fully developed scopa ( Figs. 28A, 28B ) or mesosoma coarsely sculptured on pleuron and carina appearing to reach dorsal surface ( Figs. 28C, 28D ); male metasomal sterna with erect pubescence; male antennae usually relatively short; male heads sometimes enlarged with long mandibles ( Fig. 28E )....... L . ( Hemihalictus ) - Either propodeum with weak lateral carina and highly modified reduced scopa ( Figs. 29A, 29B ) or mesosoma weakly rugose at most and propodeum with complete carina ( Figs. 29C, 29D ); male metasomal sterna nearly bare, except in Onagraceae specialists; male antennae relatively long ( Fig. 4C ); male heads not enlarged ( Fig. 4B ).............. L. ( Sphecodogastra )