Lasioglossum, Curtis, 1833

Hettiarachchi, Thilina & Gibbs, Jason, 2024, A problematic species complex for Lasioglossum subgeneric diagnostics in North America (Hymenoptera: Halictidae), Zootaxa 5404 (1), pp. 206-235 : 226

publication ID	https://doi.org/ 10.11646/zootaxa.5404.1.13
publication LSID	lsid:zoobank.org:pub:A902495B-8A81-4F33-BA18-B8E3E79FA6A9
DOI	https://doi.org/10.5281/zenodo.10592491
persistent identifier	https://treatment.plazi.org/id/03A087C0-FFC2-FFDB-FF39-4CBFEB8EF829
treatment provided by	Plazi
scientific name	Lasioglossum
status

Treatment

Key to Lasioglossum View in CoL 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 View FIGURE 16 ), 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 View FIGURE 17 ); body length usually greater (approx. 7–12 mm)..................... 2

- Second submarginal crossvein (1rs-m) weaker than first (second abscissa of Rs) ( Fig. 16B View FIGURE 16 ), 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 View FIGURE 17 )....................................... 3

2. Propodeum with lateral carina well developed, reaching dorsal surface ( Fig. 18A View FIGURE 18 ); dorsal surface coarsely sculptured, shorter than scutellum ( Fig. 18A View FIGURE 18 ); T1 without basal hair band ( Fig. 18A View FIGURE 18 ); head long (length/width ratio = 0.88–1.0) ( Fig. 19A View FIGURE 19 ); male gonostylus without retrorse lobe ( Fig. 20A View FIGURE 20 )................................................... L. (Leuchalictus)

- Propodeum with lateral carina usually poorly developed, not reaching dorsal surface ( Fig. 18B View FIGURE 18 ), but if strong ( Figs. 18C, 18D View FIGURE 18 ) then dorsal surface longer than scutellum ( Fig. 18C View FIGURE 18 ) or weakly sculptured ( Fig. 18C View FIGURE 18 ) or T1 with basal hair band or head short ( Fig. 18D View FIGURE 18 ) (length/width ratio = 0.77–0.89) ( Fig. 19B View FIGURE 19 ); male gonostylus with retrorse lobe ( Fig. 20B View FIGURE 20 ).... L. ( Lasioglossum View in CoL )

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 View FIGURE 21 ) in North American species (except L. ruidosense View in CoL and L. petrellum (Cockerell) View in CoL species complexes, L. microlepoides (Ellis) View in CoL , L. pavoninum (Ellis)) View in CoL , typically lacking erect hairs medially; female mandible almost always with small preapical tooth ( Fig. 21B View FIGURE 21 ), except in the wood-nesting L. coeruleum (Robertson)) View in CoL (cosmopolitan)............................................ L. (Dialictus)

- Body size usually larger (6–8 mm); female T1 without appressed hairs, medially with distinct erect hairs ( Fig. 22A View FIGURE 22 ); female mandible often strongly bidentate ( Fig. 22B View FIGURE 22 ), if preapical tooth small, then propodeum with distinct lateral carina reaching dorsal margin (primarily from Panama to Mexico, except L. aquilae View in CoL , which reaches to high elevation areas in the southwestern USA)................................................................................ L. (Eickwortia s.l.)

6 (3). Head wide ( Fig. 23A View FIGURE 23 ); female inner metatibial spur with fine oblique teeth, not as tall as width of main rachis ( Fig. 23A View FIGURE 23 ); male gonostylus without retrorse lobe; metasomal sterna with erect pubescence.............................. L. ( Evylaeus )

- Head usually longer ( Fig. 23B View FIGURE 23 ); female inner metatibial spur usually with longer, narrow or fat teeth, often taller than width of main rachis basally ( Fig. 24B View FIGURE 24 ); male gonostylus with retrorse lobe; metasomal sterna with variable pubescence.......... 7

7. Foretibia of female with long projection ( Fig. 25A View FIGURE 25 ); metapostnotum enclosed by carina, with distinct parallel carinulae ( Fig. 26A View FIGURE 26 ); frons with two bulbous protuberances ( Fig. 26B View FIGURE 26 ); retrorse lobe absent (Neotropical)....................................................................... L. gattaca View in CoL complex ( L. gattaca View in CoL and L. hartmanni Danforth and Wcislo View in CoL )

- Foretibia of female without long projection ( Fig. 25B View FIGURE 25 ); metapostnotum not as above; retrorse lobe present (widespread)... 8

8. Female mandible strongly bidentate ( Fig. 27 View FIGURE 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 View FIGURE 28 ) or mesosoma coarsely sculptured on pleuron and carina appearing to reach dorsal surface ( Figs. 28C, 28D View FIGURE 28 ); male metasomal sterna with erect pubescence; male antennae usually relatively short; male heads sometimes enlarged with long mandibles ( Fig. 28E View FIGURE 28 )....... L. (Hemihalictus)

- Either propodeum with weak lateral carina and highly modified reduced scopa ( Figs. 29A, 29B View FIGURE 29 ) or mesosoma weakly rugose at most and propodeum with complete carina ( Figs. 29C, 29D View FIGURE 29 ); male metasomal sterna nearly bare, except in Onagraceae View in CoL specialists; male antennae relatively long ( Fig. 4C View FIGURE 4 ); male heads not enlarged ( Fig. 4B View FIGURE 4 ).............. L. ( Sphecodogastra )