Lasioglossum (Dialictus) laevissimum (Smith)

Gibbs, Jason, 2011, Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini), Zootaxa 3073, pp. 1-216 : 129-130

Lasioglossum (Dialictus) laevissimum (Smith)

Halictus laevissimus Smith, 1853: 72 . Ƥ.

Holotype. Ƥ Canada, Manitoba, Arctic America. South of Lake Winnipeg, [ BMNH: B.M. Type 17a 1002]. Examined. Halictus levissimus Dalla Torre, 1896: 68 (Emend.)

Halictus euryceps Ellis, 1914: 98 . Ƥ.

Holotype. Ƥ USA, New Mexico, Beulah, end of August, (Cockerell); [ CAS: 15605]. Examined. Halictus (Chloralictus) phaceliarum Cockerell, 1919: 299 . Ƥ.

Holotype. Ƥ USA, Colorado, Peaceful Valley, Colorado, 26.viii.1918 (W.P. Cockerell); [ NMNH: 40260]. Examined. Halictus (Chloralictus) praepes Sandhouse, 1924: 30 . 3.

Holotype. 3 USA, Colorado, Peaceful Valley, 1919 (Cockerell); [ NMNH: 26430]. Examined. Halictus (Chloralictus) astutus Sandhouse, 1924: 31 . 3.

Holotype. 3 USA, New Mexico, Beulah, 18.viii. (W. Porter); [ NMNH: 26431]. Examined. Halictus (Chloralictus) abundus Sandhouse, 1924: 32 . 3.

Holotype. 3 USA, New Mexico, Beulah, end of viii (Cockerell); [ NMNH: 26432]. Examined. Halictus (Chloralictus) tranquillum Sandhouse, 1924: 32 . 3.

Holotype. 3 USA, New Mexico, Santa Fe, vii (Cockerell); [ NMNH: 26433]. Examined. Halictus (Chloralictus) jameseae Cockerell, 1933: 41 . 3.

Holotype. 3 USA, Colorado, Pingree Park, 15.viii.1932, (M. James); [ CAS: 15610]. Examined. Dialictus orbitatus Mitchell, 1960: 440 . 3. [new synonymy]

Holotype. Ƥ USA, North Carolina, Bluff Park, Scenic Hgwy. , [Doughton Park, Blue Ridge Pkwy], 24.vi.1948 (T.B. Mitch-

ell); [ NCSU]. Examined.

Dialictus solidaginis Mitchell, 1960: 443 . 3.

Holotype. 3 USA, Michigan, Marquette Co., 20.vi.1955 (R.R. Dreisbach); [ NCSU]. Examined.

Taxonomy. Cockerell, 1905: Halictus laevissimus Ƥ, p. 351 (tax. notes); Michener, 1951: Lasioglossum (Chloralictus) abundus , p. 1111, L. (C.) astutus p. 1112, L. (C.) jameseae , p. 1114, L. (C.) laevissimum , p. 1114, L. (C.) phaceliarum , p. 1116, L. (C.) praepes , p. 1116, L. (C.) tranquillum , p. 1118 (catalogue); Mitchell, 1960: Dialictus laevissimus Ƥ(3 misdet.), p. 401 (redescription, key); Knerer & Atwood, 1962a: Dialictus laevissimus 3, p. 1228 (description); Krombein, 1967: Lasioglossum (Dialictus) laevissimum , p. 464, L. (D.) orbitatum , p. 465, L. (D.) solidaginis , p. 466 (catalogue); Hurd, 1979: Dialictus abundus , p. 1963, D. astutus , p. 1964, D. jameseae , p. 1967, D. orbitatus , p. 1969, D. phaceliarum , p. 1970, D. praepes , p. 1970, D. solidaginis , p. 1971, D. tranquillus , p. 1972 (catalogue); Moure & Hurd, 1987: Dialictus abundus , p. 87, D. astutus , p. 91, D. jameseae , p. 109, D. orbitatus , p. 118, D. phaceliarum , p. 121, D. praepes , p. 124, D. solidaginis , p. 130, D. tranquillus , p. 135 (catalogue); Gibbs, 2010b: Lasioglossum (Dialictus) laevissimum Ƥ3, p. 170 (redescription, key, synonymies).

Diagnosis. Female L. laevissimum can be recognised by the following diagnostic combination: size large (5.1–7.1 mm); head wide (length/width 0.89–0.95); gena often wider than eye, especially in larger individuals; mesoscutal punctures sparse between parapsidal lines (i=1–3d); mesepisternum rugulose; metapostnotum incompletely carinulate; T1 acarinarial fan nearly complete, dorsal opening narrow; metasomal terga blackish brown, apical halves impunctate (except along premarginal line), and T3 usually with sharply contrasted basal band of white tomentum. They are similar to L. smilacinae , which lacks any dorsal opening in the T1 acarinarial fan, and have metasomal terga with distinctly punctate apical impressed areas.

Male L. laevissimum can be recognised by the following diagnostic combination: size large (5.4–6.7 mm); face with dense tomentum limited to lower paraocular area; flagellomeres elongate (length/width ratio = 1.64–2.00); mesoscutum moderately polished due to weak microsculpture; mesepisternum rugulose, obscurely punctate ventrally; apical impressed areas of metasomal terga impunctate; and S3 with dense hairs. They are most similar to L. abanci and L. ephialtum . Male L. abanci have S3 with sparse hairs limited to apical portion. Male L. ephialtum , which has the mesoscutum dull due to microsculpture.

Range. Nova Scotia west to British Columbia, south to New Mexico. USA: CO, IL, MD, ME, MI, MN, NC, ND, NH, NM, NY, OH, PA, SD, UT, WI, WV. CANADA: AB, BC, MB, NB, NF, NS, NT, ON, PE, PQ, SK.

DNA Barcode. Available. Multiple sequences.

Comments. Common.

Lasioglossum laevissimum is known to form eusocial colonies ( Packer 1992; Packer & Owen 1994).

Dialictus orbitatus is removed from synonymy with L. obscurum and placed into synonymy with L. laevissimum . Halictus smilacinae , long considered to be a synonym of L. laevissimum , is resurrected (see below).