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Extracted from: Gibbs, J., Packer, L., Dumesh, S. and Danforth, B. N. 2013. Revision and reclassification of Lasioglossum (Evylaeus), L. (Hemihalictus) and L. (Sphecodogastra) in eastern North America (Hymenoptera: Apoidea: Halicidae). Zootaxa 3672 (1). Pp 1-116.
Diagnosis. Both sexes of L. birkmanni can be recognised by the combination of head short (L/W ratio = 0.94–1.00)
(Figs. 4A, 6A); pronotum smoothly rounded dorsolaterally; and mesepisternum distinctly punctate (as in Fig. 76B).
Lasioglossum birkmanni can be easily distinguished from most species, except L. macoupinense. Both sexes of L.
macoupinense have head longer (L/W ratio = 1.02–1.09) (Figs. 4F, 6F). Female L. macoupinense have sparser
punctation on the supraclypeal area (i=1–2.5d) than do L. birkmanni (i=1–1.5d). Male L. macoupinense have
longer setae on the gonostylus (Fig. 7F).
Redescription. FEMALE. Length 4.8–6.3 mm. Head length 1.27–1.55 mm. Head width 1.35–1.65 mm. Wing
length 3.9–4.8 mm. (n=5)
Colour. Head and mesosoma black. Antenna black, except ventral surface of flagellum reddish brown. Tegula
pale yellow-testaceous. Legs dark brown, except medio- and distitarsi reddish brown. Wing membrane hyaline,
faintly dusky. Pterostigma brown. Metasomal terga black-brown, apical margins pale brown.
Structure. Head wide (L/W ratio = 0.94–0.97). Clypeus 2/3 below suborbital line. Eyes strongly
convergent below (UOD:LOD = 1.28–1.42). Gena narrower than eye. Ocelli normal. Pronotum smoothly
rounded. Protibial spur with apical serrations shorter than width of malus. Inner metatibial spur pectinate, teeth
4–5, basal teeth longer than width of rachis. Propodeal lateral carina not reaching dorsal margin, oblique carina
low, obscure.
Surface sculpture. Supraclypeal area imbricate, punctures dense (i≤d). Gena and postgena lineolate.
Mesoscutum polished; punctures dense laterally (i≤d), distinctly separated between parapsidal lines (i=1–2d).
Mesepisternum smooth, polished, distinctly punctate. Metapostnotum carinate-rugose basally, apical margin
weakly imbricate. Propodeum imbricate-tessellate. Metasomal terga polished, apical impressed areas weakly
coriarious; punctures dense, obscure posteromedially.
Pubescence. Head and mesosoma with sparse plumose hairs. Metafemoral scopa with dense plumose hairs.
Propodeum with sparse plumose hairs. Metasomal terga with sparse apical fimbriae. T1 with sparse, erect plumose
hairs. T2–T3 with basolateral patches of dense tomentum. Metasomal sterna with plumose scopa.
MALE. Length 4.2–5.5 mm. Head length 1.20–1.43 mm. Head width 1.24–1.48 mm. Wing length 3.3–4.1
mm. (n=6)
Colour. Head and mesosoma black. Clypeus apical half yellow. Mandible brown basally, yellow apically.
Labrum yellow. Antenna black, except ventral surface of flagellum brown. Legs dark brown, except tarsi, bases
and apices of pro- and mesotibiae yellow, protibia largely yellow-testaceous. Tegula pale yellow. Wing membrane
hyaline. Pterostigma pale brown. Metasomal terga dark brown.
Structure. Head wide (L/W ratio = 0.95–1.00). Mandible short, reaching opposing clypeal angle.
Flagellomeres, except F1, moderately elongate, F2 shorter than F1 and pedicel combined, much shorter than scape.
Eyes convergent below (UOD:LOD = 1.53–1.64). Gena narrower than eye. Pronotum smoothly rounded.
Propodeal lateral carina nearly reaching dorsolateral slope.
Surface sculpture. Supraclypeal area weakly imbricate; punctures dense, shallow (i≤d). Gena and postgena
lineolate. Mesoscutum polished; punctures fine, dense laterally (i≤d), well-separated between parapsidal lines
(i=1–2d). Mesepisternum polished, distinctly punctate. Metapostnotum on basal half carinate-rugose, apical
margin imbricate. Propodeum lateral surface weakly rugulose-imbricate, posterior surface weakly imbricate.
Metasomal terga polished; punctures deep, close basally. T2–T6 apical impressed areas with sparse, scattered
punctures.
Pubescence. Head and mesosoma with sparse plumose hairs. Paraocular area below eye emargination with
relatively sparse tomentum. Propodeum largely bare, with scattered plumose hairs. Metasomal terga nearly bare,
apical fimbriae extremely sparse. Metasomal sterna with sparse, plumose hairs (1.5–2 OD).
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