Lasioglossum (Dialictus) heterognathum (Mitchell)

Dialictus heterognathus Mitchell, 1960: 397 . Ƥ.

Holotype. Ƥ USA, North Carolina, Grandfather Mt., 27.vi.1952, [NCSU]. Examined. Dialctus banksi Mitchell, 1960: 434 . 3. Lapsus calami .

Holotype. 3 USA, North Carolina, West End, 14.vi.1950, (Mitchell); [NCSU]. Examined.

Taxonomy. Knerer and Atwood, 1963: Dialictus heterognathus 3, p. 167 (description); Knerer and Atwood, 1966a: D. heterognathus, p. 882 (synonymy); Krombein, 1967: Lasioglossum (Dialictus) heterognathum, p. 463 (catalogue); Hurd, 1979: Dialictus heterognathus, p. 1966 (catalogue); Moure & Hurd, 1987: Dialictus heterognathus, p. 103 (catalogue); Gibbs, 2010b: Lasioglossum (Dialictus) heterognathum Ƥ3, p. 136 (redescription, key).

Diagnosis. Female L. heterognathum can be recognised by the following diagnostic combination: hypostomal carinae divergent towards mandible bases (Fig. 10 B), gena wider than eye, mesoscutal punctures fine, and scopa present. They are similar to L. apocyni and L. imitatum, which both have hypostomal carinae parallel and female L. imitatum have T3–T4 with coarse white hairs (Fig. 20 A).

Male L. heterognathum can be recognised by the following diagnostic combination: facial tomentum dense only on lower paraocular area; flagellomeres elongate (length/width ratio = 1.50–1.85); dorsolateral angles of pronotum obtuse; mesoscutum dull due to weak microsculpture, punctures sparse between parapsidal lines (i=2–3d); mesepisternal punctures fine but distinct (i=1–3d); and apical impressed areas of the metasomal terga impunctate. They are most similar to L. wheeleri, which have pronotal dorsolateral angles acute.

Range. Nova Scotia to Ontario, west to Minnesota, and south to North Carolina. USA: CT, ME, MI, MN, NH, NY, NC, PA, VT, WV, WI. CANADA: NB, NS, ON, PQ.

DNA Barcode. Available. Multiple sequences.

Comments. Common. See Gibbs (2010b).