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 ) mitchelli Gibbs Dialictus atlanticus Mitchell, 1960 : 383 . Ƥ. (junior secondary homonym of Halictus interruptus atlanticus Cockerell, 1938b ) Holotype . Ƥ USA , North Carolina, Raleigh , 5.viii.1957 (Mitchell); [NCSU]. Examined. Lasioglossum ( Dialictus ) mitchelli Gibbs, 2010b : 194 . Ƥ3. (redescription, replacement name for D . atlanticus Mitchell ). Taxonomy. Knerer and Atwood, 1966a : Dialictus atlanticus 3, p. 881 (description); Krombein, 1967 : Lasioglossum ( Dialictus ) atlanticum , p. 462 (catalogue); Hurd, 1979 : Dialictus atlanticus , p. 1964 (catalogue); Moure & Hurd, 1987 : Dialictus atlanticus , p. 91 (catalogue). Diagnosis. Female L . mitchelli can be recognised by the shape of the clypeus, which has the distal margin beyond the preapical fimbriae extending laterally making it noticeably wider than the preapical margin ( Fig. 21 B). The distal portion of the clypeus has a rectangular appearance as a result. They may be further distinguished by the combination of head wide (length/width ratio = 0.90–0.94); mesoscutum tessellate, punctures moderately dense between parapsidal lines (i=1– 1.5d); mesepisternum rugulose; tegula pale straw; T1 declivitous surface with distinct, coriarious microsculpture, and acarinarial fan usually without dorsal opening. They are similar to some members of the L . viridatum species-group such as L . paradmirandum . Females of the L . viridatum species-group have the clypeus distinctly convergent towards the apex, T1 is often polished and the acarinarial fan usually has a distinct dorsal opening. Male L . mitchelli are similar to females but have a more elongate head length/width ratio = 0.98–1.00) and may be further distinguished by flagellomeres elongate (length/width ratio = 1.73–1.90), tarsi and tibial apices brownish yellow, metapostnotum with posterior margin weakly carinate, and apical impressed areas of metasomal terga impunctate. They are most similar to L . versatum and L . paradmirandum . Male L . versatum have distinct punctures on apical impressed areas of metasomal terga. Male L . paradmirandum have posterior margin of metapostnotum rounded. Range. Ontario south to Georgia , west to Kansas. USA : IA, IL , IN, KS, MA, MD, MI, MO, PA, NC, NJ, NY, SC, TN, TX, VA, WI, WV. CANADA : ON. Floral records. ASTERACEAE : Flaveria linearis . DNA Barcode. Available. Multiple sequences. Comments. Very common. The original name given to this species is invalid due to secondary homonymy ( Ebmer 1976 ; Gibbs 2010b ).