Lasioglossum viridatum (Lovell, 1905)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 57

The Lasioglossum viridatum species-group

Species included. Lasioglossum absimile (Sandhouse) , L. admirandum , L. apocyni , L. atwoodi , L. dreisbachi , L. ephialtum , L. fattigi , L. marinense , L. novascotiae , L. oblongum , L. obscurum , L. pacatum , L. paradmirandum , L. planatum , L. sablense , L. sagax , L. subviridatum , L. taylorae , L. viridatulum (Cockerell) and L. viridatum .

Diagnosis. The viridatum species-group includes many nondescript and closely related species which have caused much difficulty in Dialictus identifications. The group does not have a simple character or combination of characters that allow members to be easily diagnosed but in some sense is recognisable by the lack of such characters. Body size is variable (approximately 4–7 mm) but usually typical (approximately 5–6 mm), head width usually wide to round, sometimes moderately elongate (length/width ratio = 0.93–1.05), clypeus apicolateral margins distinctly convergent, gena usually narrower than eye, mesoscutal punctures fine, sparse or moderately sparse between parapsidal lines and usually denser laterally, mesepisternum usually rugulose with at most indistinct punctures, sometimes tessellate or coarsely rugose, tegula ovoid, metapostnotum rugoso-striate sometimes reaching posterior margin, propodeum with weak oblique carina, lateral carina not reaching dorsal margin, metasomal terga brown to black with at most faint metallic reflections, T1 acarinarial fan usually with clear dorsal opening (closed in two undescribed species possibly belonging to this group), terga with tomentum abundant to absent, punctures usually present on apical impressed areas but often sparse or obscure. Males of some species have a distal band of yellow on the clypeus. Lasioglossum versatum is very similar but has very dense and distinct punctures on the apical impressed areas of the metasoma.

Distribution. The viridatum group is common and widespread throughout Canada and large parts of the USA. The group becomes less diverse and uncommon towards the southwestern states of the USA.