Lasioglossum (Dialictus) pruinosum (Robertson)

Halictus pruinosus Robertson, 1892: 269 . Ƥ 3.

Lectotype. Ƥ USA, Illinois, Macoupin Co., Carlinville, 22.v.1891 (C. Robertson); [INHS: 11121] by W. E. LaBerge (in Webb 1980). Examined.

Taxonomy. Robertson, 1902b: Chloralictus pruinosus, p. 248 (key); Cockerell, 1909: Halictus pruinosus, p. 9 (tax. comp.); Michener, 1951: Lasioglossum (Chloralictus) pruinosum, p. 1116 (catalogue); Mitchell, 1960: Dialictus pruinosus Ƥ3, p. 415. (redescription); Krombein, 1967: Lasioglossum (Dialictus) pruinosum, p. 465 (catalogue); Dialictus pruinosus, p. 1970 (catalogue); Moure & Hurd, 1987: Dialictus pruinosus, p. 125 (catalogue); Gibbs, 2010b: Lasioglossum (Dialictus) pruinosum Ƥ3, p. 269 (redescription, key).

Diagnosis. Female L. pruinosum can be recognised by the following diagnostic combination: head long (length/ width ratio = 1.05–1.09); mesoscutal punctation dense (i<d), except on medial portion (i=1–1.5d); mesepisternum rugulose; wings hyaline; pterostigma nearly white pterostigma; and metasomal terga with abundant tomentum. They are most similar to L. succinipenne, which has the mesoscutal punctures dense throughout.

Male L. pruinosum can be recognised by the following diagnostic combination: head long (length/width ratio = 1.18–1.21), covered in dense white tomentum; clypeus with distal yellow maculation; flagellomeres short (length/width ratio = 1.15–1.30), bright yellow ventrally; mesoscutal punctation moderately sparse medially (i=1–2d); mesepisternum rugoso-reticulate; and metasomal terga bluish green, distinctly punctate. They are most similar to L. albipenne, which lacks yellow on clypeus and have brown metasomal terga.

Range. British Columbia and south to Arizona east to north-eastern USA. USA: AZ, CO, IA, ID, IN, MI, MN, NE, TX, UT, WI. CANADA: AB, BC, MB, SK.

DNA Barcode. Available. Multiple sequences.

Comments. Uncommon in the eastern United States. See Gibbs (2010).