Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini) Author Gibbs, Jason text Zootaxa 2011 2011-10-28 3073 1 216 journal article 31531 10.5281/zenodo.1049595 1a985cc7-af57-45e9-a988-c3beda3c15b4 1175-5326 1049595 B5AF6DF4-D3A7-4942-A94F-CC051D8074CF 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).