Lasioglossum (Dialictus) mitchelli Gibbs

Gibbs, Jason, 2011, Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini), Zootaxa 3073, pp. 1-216 : 148

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).

Figures

FIGURE 21. Margin of clypeus (A) L. admirandum, (B) L. mitchelli.