Lasioglossum (Dialictus) weemsi (Mitchell)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 355-358

Lasioglossum (Dialictus) weemsi (Mitchell)

( Figure 238A–C )

Dialictus weemsi Mitchell, 1960: 431 . ♀.

Holotype. ♀ USA, North Carolina, Wake Co., 16.vi.1955 on Melilotus officinalis (H.V. Weems, Jr.) ; [ FSCA]. Examined.

Taxonomy. Krombein, 1967: Lasioglossum (Dialictus) weemsi , p. 467 (catalogue); Dialictus weemsi , p. 1973 (catalogue); Moure & Hurd, 1987: Dialictus weemsi , p. 140 (catalogue).

Diagnosis. Females of L. weemsi can be recognised by the shape of the clypeus which has subparallel apicolateral margins, acute apicolateral angles and a broad, straight distal margin. They may be further distinguished by the round head (length/width ratio = 0.90–0.94), tessellate mesoscutum with moderately dense punctures on the central disc (i=1–1.5d), rugulose mesepisternum, pale tegula, and T1 acarinarial fan with dorsal opening. They differ from L. mitchelli which lacks a dorsal opening on the T1 acarinarial fan. Lasioglossum weemsi is similar to some members of the L. viridatum species-group such as L. admirandum and L. paradmirandum . Females of the L. viridatum species-group have the clypeus distinctly convergent towards the apex and a distinct dorsal opening of the acarinarial fan.

Male unknown.

Redescription. FEMALE. Length 4.24–4.90 mm; head length 1.27–1.49 mm; head width 1.32–1.58 mm; forewing length 3.21–3.81 mm.

Colouration. Head and mesosoma green with faint bluish reflections to mostly blue. Clypeus with apical half blackish brown. Antenna dark brown, flagellum with ventral surface ruddy. Mesoscutum sometimes with brassy reflections. Tegula amber to reddish. Wing membrane subhyaline, venation and pterostigma brownish yellow. Legs brown, tarsi reddish brown to amber. Metasoma dark brown, terga and sterna with apical margins translucent brownish yellow.

Pubescence. Dull white. Moderately sparse. Head and mesosoma with moderately sparse woolly hairs (1– 2 OD), longest on genal beard, metanotum and mesopleuron (2–2.5 OD). Paraocular area with moderately sparse tomentum, partially obscuring surface. Gena with sparse tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with moderately sparse, fine setae. T1 acarinarial fan with distinct dorsal opening. T2–T3 basolaterally and T4 entirely with sparse tomentum. T2 apicolateral and T3–T4 apical margins with sparse fringes.

Surface sculpture. Face imbricate, punctation fine. Clypeus with apical half polished, punctation sparse (i=1–3d). Supraclypeal area with punctation moderately sparse (i=1–2.5d). Lower paraocular area punctation dense (i≤d). Antennocular area punctation moderately dense (i=1–1.5d). Upper paraocular area and frons punctate-reticulate. Ocellocular area obscurely punctate (i=d). Gena lineolate. Postgena imbricate. Mesoscutum tessellate, punctation moderately dense between parapsidal lines (i=1–1.5d), dense laterad of parapsidal lines (i≤d), contiguous on anterolateral portion. Mesoscutellum similar to mesoscutum, submedial punctation sparse (i=2–5d). Axilla minutely punctate. Metanotum imbricate. Preëpisternum rugose. Hypoepimeral area strongly imbricate-lineolate. Mesepisternum dorsal half rugulose, ventral half ruguloso-imbricate. Metepisternum with dorsal two-fifths striate, ventral portion imbricate. Metapostnotum incompletely striate, posterior margin imbricate. Propodeum with dorsolateral slope rugulose, lateral surface tessellate-imbricate, posterior surface tessellate. Metasomal terga faintly coriarious, punctation uniformly spaced on disc (i=1–1.5d) except apical impressed area nearly impunctate.

Structure. Head very wide (length/width ratio = 0.93–0.96). Eyes convergent below (UOD/LOD ratio = 1.23–1.29). Clypeus ½ below suborbital tangent, apicolateral angle subparallel. Antennal sockets close (IAD/ OAD <0.5). Frontal line carinate, ending 2 OD below median ocellus. Gena narrower than eye. Inner metatibial spur pectinate with 3–4 teeth. Metapostnotum truncate (MMR ratio = 1.23–1.29), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina absent, lateral carina not reaching dorsal margin.

MALE. Unknown.

Range. Southern Ontario south to South Carolina ( Fig. 239 ).

Additional materal examined. CANADA: ONTARIO: 1♀ Norfolk Co., Pterophylla Plant Nursery , N42°38.404´W080°34.379´, 13–22.viii.2006 (P.J. Carson) ; 1♀ York University Keele Campus , nr CSEB , 6.vi.2006 (E. Willis); 1♀ York University Keele Campus, nr Pond Rd. residences, 28.vii.2005 (E. Willis); [ PCYU] ; USA: ILLINOIS: 1♀ E of Carlinville , N39.2596 W089.5485, 25.vi.2006 (J. Gibbs) ; 1♀ Macoupin Co., E of Carlinville , N39.27869 W089.7961, 25.vi.2006 (C. Sheffield) ; MARYLAND: 2♀ Pr. George’s Co., N39.0352 W076.8739, 21.vii.2004 (S. Kolski) ; NEW YORK: 1♀ Hwy 63, N of Genesio, N42.8235 W077.7425, 11.vi.2006 (J. Gibbs); [ PCYU] ; NORTH CAROLINA: 1♀ Blue Ridge Pkwy, nr Jefferson , N36.34234 W081.37465, 13.viii.2006 (J. Gibbs) ; PENNSYLVANIA: 1♀ Philadelphia Co., N39.9628 W075.1773, 23.viii.2005 (S.W. Droege) ; SOUTH CAROLINA: 2♀ Okanee Co., nr Walhalla , N34.80472 W083.14587, 9.viii.2006 (J. Gibbs) ; TENNESSEE: 1♀ Hwy 321, nr Gatlinburg , N35.7599 W083.3615, 8.viii.2006 (J. Gibbs) ; VIRGINIA: 1♀ Hwy 21, 8 km S of Elk, N36.68854 W081.17776, 14.viii.2006 (J. Gibbs) ; WEST VIRGINIA: 1♀ nr Charleston , N38.41211 W081.64776, 13.viii.2006 (J. Gibbs); [ PCYU] ; WISCONSIN: 1♀ Kewaunee Co., They’s Ag , N44.53102 W87.70013, 23.v.2006 (J. Watson); [ ARC] .

Comments. Common. Lasioglossum weemsi is very similar to L. mitchelli , apparently only differing in the T1 acarinarial fan and the DNA barcodes. Additional study is needed to test if these two warrant being recognised as distinct. A third species, L. leviense (Mitchell) , known from the Southeastern United States, is also part of this complex. If one day these three are considered to be synonymous then L. leviense has page priority over L. weemsi .

Figures

FIGURE 238. Lasioglossum weemsi (Mitchell). Female (A) lateral habitus; (B) dorsal habitus; (C) face. Scale bars, A– C = 1 mm.

FIGURE 239. Distribution of Lasioglossum weemsi (light grey) and L. yukonae (dark grey).