Lasioglossum (Dialictus) ceanothi (Mitchell)

Gibbs, Jason, 2011, Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini), Zootaxa 3073, pp. 1-216 : 66-67

Lasioglossum (Dialictus) ceanothi (Mitchell)

( Figure 75–76 )

Dialictus ceanothi Mitchell, 1960: 386 . Ƥ.

Holotype. Ƥ USA, North Carolina, Wayne Co. , 15.vi.1955, on Ceanothus americanus, (H.V. Weems, Jr.) ; [ FSCA]. Examined.

Taxonomy. Krombein, 1967: Lasioglossum (Dialictus) ceanothi , p. 463 (catalogue); Hurd, 1979: Dialictus ceanothi , p. 1965 (catalogue); Moure & Hurd, 1987: Dialictus ceanothi , p. 94 (catalogue).

Diagnosis. Female L. ceanothi can be recognised by the following diagnostic combination: head wide (length/width ratio = 0.90) ( Fig. 75 B); mesoscutal punctures relatively coarse, moderately dense between parapsidal lines (i=1–1.5d) ( Fig. 76 ); mesepisternum reticulate-rugose; propodeal carinae weak; and T1 polished with acarinarial fan sparse but lacking a dorsal opening. They are similar to L. foveolatum and L. timothyi . Female L. foveolatum have supraclypeal area strongly protuberant lower paraocular area sparsely punctate, and parapsidal lines deep and wide. Female L. timothyi have strong propodeal carinae ( Fig. 25 A) and T1 acarinarial fan dense.

Male unknown.

Description. FEMALE. Length 4.84–5.00 mm; head length 1.40–1.42 mm; head width 1.53–1.57 mm; forewing length 3.75–3.88 mm.

Colouration. Head and mesosoma golden green with some faint bluish reflections. Clypeus with apical half blackish brown, basal half and supraclypeal area bronze. Antenna dark brown, F2–F10 with ventral surface reddish brown. Tegula amber. Wing membrane subhyaline, venation and pterostigma amber. Legs brown, except tarsi reddish brown. Metasoma dark brown, terga and sterna reddish apically.

Pubescence. Dull white. Moderately sparse. Head and mesosoma with moderately dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum, and mesopleuron (2–2.5 OD). Lower paraocular area and gena with sparse subappressed tomentum not obscuring surface. Metanotum anteromedial margin with tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metepisternum without tomentum. Metasomal terga with moderately dense, fine hairs. T1 acarinarial fan sparse, complete dorsally. T2–T3 basolaterally and T4 entirely with tomentum partially obscuring surface. T2 apicolateral and T3–T4 apical margins with dense apical fringes.

Surface sculpture. Face imbricate, punctation moderately coarse. Clypeus polished, basal margin imbricate, punctation moderately dense (i=1–2d). Supraclypeal area with punctation moderately dense (i=1–1.5d). Lower paraocular area punctation dense (i≤d). Antennocular area punctation moderately dense (i=1–1.5d). Upper paraocular area and frons reticulate-punctate. Ocellocular area distinctly punctate (i≤d). Gena and postgena weakly carinulate. Mesoscutum weakly imbricate, nearly polished except medially, punctation moderately coarse and dense between parapsidal lines (i=1–1.5d), dense laterad of parapsidal line (i≤d), and anterolateral portion punctate-reticulate. Mesoscutellum polished, submedial area punctation sparse (i=1.5–2.5d). Axilla punctate. Metanotum ruguloso-imbricate. Preëpisternum rugose. Hypoepimeral area and mesepisternum reticulate-rugose. Metepisternum with dorsal half rugoso-carinulate, ventral half imbricate. Metapostnotum with coarse rugae reaching posterior margin, submedially with anastomosing rugae. Propodeum with dorsolateral slope carinulate anteriorly, rugulose-imbricate posteriorly, lateral surface rugulose-imbricate, posterior surface tessellate. Metasomal terga polished except apical T1 declivitous surface and apical impressed areas weakly coriarious. T1 dorsal surface punctation sparse (i=2–5d). T2–T4 punctation moderately sparse medially (i=1–3d), denser laterally (i=1–1.5d).

Structure. Head very wide (length/width ratio = 0.90–0.92). Eyes convergent below (UOD/LOD ratio = 1.22–1.27). Clypeus 1/2 below suborbital tangent, apicolateral margins convergent. Antennal sockets close (IAD/OAD <0.5). Frontal line carinate, ending 2 OD below median ocellus. Supraclypeal area distinctly convex. Inner metatibial spur pectinate with 3 branches. Metapostnotum moderately elongate (MMR ratio = 1.13–1.17), narrowly rounded onto posterior surface. Propodeum with oblique carina virtually absent, lateral carina reaching 2/3 distance to dorsal margin.

MALE. Unknown.

Range. North Carolina, north to Michigan, west to Missouri ( Fig. 74 ). USA: MI, MO, NC.

Additional material examined. MICHIGAN: 1Ƥ paratype [head glued to label not conspecific] Mackinac Co., 6.vii.1957 (R. & K. Dreisbach); [ CUIC]; MISSOURI: 1Ƥ paratype Willard, 11.vi (A.E. Brower); [ CUIC]; NORTH CAROLINA: 1Ƥ paratype Wayne Co. 15.vi.1955 (H.V. Weems, Jr.); [ CUIC].

Floral records. RHAMNACEAE : Ceanothus americanus .

DNA Barcode. Unavailable.

Comments. Rare. Only specimens in the type series have been examined.

Figures

FIGURE 25. Metapostnotum (A) L. timothyi, (B) L. smilacinae. (From Gibbs 2010 b).

FIGURE 74. Distribution map of Lasioglossum batya (stars), L. ceanothi (circles) and L. cephalotes (squares).

FIGURE 75. Lasioglossum ceanothi (Mitchell) female, (A) lateral habitus, (B) face. Scale bars = 1 mm.

FIGURE 76. Lasioglossum ceanothi (Mitchell) female, dorsal view of mesosoma.