Lasioglossum (Dialictus) coeruleum (Robertson)

Halictus coeruleus Robertson, 1893: 146 . Ƥ 3.

Lectotype. Ƥ USA, Illinois, Macoupin Co., Carlinville, 10.iv.1889 (C. Robertson); [INHS: 8806] by W. E. LaBerge (in Webb 1980). Examined.

Taxonomy. Robertson, 1902b: Chloralictus caeruleus, p. 248 (key); Viereck, 1916: Halictus (Chloralictus) caeruleus, p. 706; Michener, 1951: Lasioglossum (Chloralictus) coeruleum, p. 1113. (catalogue); Mitchell, 1960: Dialictus coeruleus Ƥ3, p. 387 (redescription, key); Krombein, 1967: Lasioglossum (Dialictus) coeruleum, p. 463 (catalogue); Hurd, 1979: Dialictus coeruleus, p. 1965 (catalogue); Moure & Hurd, 1987: Dialictus coeruleus, p. 95 (catalogue); Pesenko et al. 2000: Evylaeus coeruleus, p. 6 (review); Gibbs, 2010b: Lasioglossum (Dialictus) coeruleum Ƥ3, p. 97 (redescription, key).

Diagnosis. Both sexes of L. coeruleum are easily recognisable by their large size (5.3–7.1 mm), body with deep metallic blue colouration (sometimes with green reflections), sparse metasomal pubescence, and mesepisternal punctures fine (sometimes obscure in females).

Range. Ontario south to Georgia, west to Kansas. USA: DE, GA, IL, IN, KS, MA, MD, MI, MN, NY, TX, VA, WI, WV. CANADA: ON, PQ.

DNA Barcode. Available. Multiple sequences.

Comments. Common.

Lasioglossum coeruleum is known to form primitively eusocial colonies in rotten logs (Stockhammer 1967).