Lasioglossum (Dialictus) perparvum

Lasioglossum (Dialictus) perparvum (Ellis, 1914) Figs 45–47, 76K, 78A, 79A, 80A, 115B, 116B Halictus perparvus Ellis, 1914: 102 (holotype, &female;, deposited in USNM, examined). Halictus pseudotegularis non auct. – Cockerell 1898: 237 (comparison to tegulare). Halictus perparvus – Cockerell 1916: 77 (comparative notes to helianthi). Halictus (Chloralictus) perparvus – Sandhouse 1924: 2 (key to species), 12 (comparison to ellisiae). Lasioglossum (Chloralictus) perparvum – Michener 1951: 1116 (catalogue). Dialictus perparvus – Hurd 1979: 1970 (catalogue). — Moure & Hurd 1987: 121 (catalogue). Diagnosis Females of L. perparvum have the tegula relatively small (reaching but not exceeding posterior margin of mesoscutum in dorsal view), with inner posterior margin straight and a blunt posterior angle, and finely, sparsely punctate laterally (IS = 1–4 PD); mesoscutum densely punctate (IS <1 PD, becoming sparser (IS = 1–2 PD) anteromedially); metapostnotum very dull, finely reticulate, with fine subparallel rugae; T2 apical rim with scattered minute punctures bearing short simple setae; T4 disc with sparse tomentum; mesoscutum with sparse erect pubescence (each seta separated by about its length from the one nearest it and some gaps more than 0.5 OD visible in lateral view) and very short intervening setae no more than stubble; and mesoscutum greenish or golden, contrasting with bluer propodeum. Females of L. perparvum are most similar to those of L. holzenthali sp. nov., L. lepidii, L. magnitegula sp. nov., and L. profundum sp. nov., all of which (except L. magnitegula) have the mesoscutum with denser erect pubescence (each seta separated by less than its length from the one nearest it and no gaps more than 0.5 OD visible in lateral view) with short intervening setae 0.25 OD long or more, mesoscutum concolourous with propodeum, and metapostnotum shiny with weak microsculpture and strong, coarse rugae. In addition, females of L. holzenthali have the T1–T3 apical rims usually deeply and distinctly punctate and L. profundum have the tegula entirely impunctate except on anterior margin. Females of L. magnitegula have the tegula much larger (clearly exceeding posterior margin of mesoscutum in dorsal view), with inner posterior margin strongly concave, and densely punctate (IS <1 PD), T2 apical rim glabrous and impunctate, and T4 disc lacking tomentum. Males of L. perparvum have the tegula relatively small (as in the female); mesoscutum tessellate anteriorly and densely punctate laterally (IS <1 PD), with sparse erect pubescence (some gaps 0.5 OD or more visible in lateral view); metapostnotum tessellate to finely reticulate with fine subparallel rugae; discs of T1–T2 deeply and moderately densely punctate (IS = 1–2 PD); and mesoscutum more greenish or golden, contrasting with bluer propodeum. Males of L. perparvum are most similar to those of L. diabolicum sp. nov., L. ellisiae, and L. magnitegula sp. nov. Males of L. diabolicum and L. ellisiae have the mesoscutum usually shiny, concolourous with the rest of the mesosoma, and with dense erect pubescence (no gaps more than 0.5 OD visible in lateral view). Males of L. magnitegula have the tegula much larger (exceeding posterior margin of mesoscutum in dorsal view), with inner posterior margin strongly concave, and densely punctate (IS <1 PD); and mesoscutum usually shiny and more coarsely punctate laterally (IS ≤1 PD). In the Neotropics there are at least two (but possibly more) very similar, undescribed species. One of these has the tegula more coarsely and densely punctate laterally (IS