Lasioglossum (Dialictus) stuartense (Mitchell)

Gibbs, Jason, 2011, Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini), Zootaxa 3073, pp. 1-216 : 181-182

Lasioglossum (Dialictus) stuartense (Mitchell)

( Figures 197 , 198 )

Dialictus stuartensis Mitchell, 1960: 419 . Ƥ.

Holotype. Ƥ USA, Florida, Stuart, 18.ix.1927 [ NCSU]

Taxonomy. Krombein, 1967: Lasioglossum (Dialictus) stuartense , p. 466 (catalogue); Moure and Hurd, 1987: Dialictus stuartensis , p. 131 (catalogue).

Diagnosis. The holotype of L. stuartense can be recognized by the following combination: size small; head round (length/width ratio = 0.98); mesoscutum imbricate-tessellate, punctures dense except medially (i=0.5–1.5d); tegula very pale yellow; mesepisternum rugulose; metapostnotal rugae reaching two-thirds distance to posterior margin; T1 acarinarial fan with dorsal opening; and metasomal terga with sparse tomentum.

Male unknown.

Redescription. FEMALE. Length 3.15 mm; head length 1.07 mm; head width 1.09 mm; forewing length 2.60 mm.

Colouration. (See comments below). Head and mesosoma weakly bluish. Clypeus with apical half reddish brown. Antenna brown, flagellum with ventral surface reddish brown. Tegula pale yellow. Wings subhyaline, venation and pterostigma brownish yellow. Legs brown, except tarsi brownish yellow. Metasomal terga and sterna brownish orange, apical margins translucent brownish yellow.

Pubescence. Dull white. Head and mesosoma with moderately dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum, and mesopleuron (2–2.5 OD). Paraocular area and gena with subappressed tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with moderately dense, fine hairs. T1 acarinarial fan with dorsal opening. T2–T3 lateral portions and T4 with sparse tomentum. T2 apicolateral and T3–T4 apical margins with sparse fringes.

Surface sculpture. Face imbricate, punctation fine. Clypeus punctation dense (i=1–2d). Supraclypeal area with punctation moderately dense (i=1–1.5d). Lower paraocular and antennocular areas with punctation dense (i≤d). Upper paraocular area, frons and ocellocular area punctate-reticulate. Gena and postgena lineolate. Mesoscutum imbricate-tessellate, punctation fine, dense on between parapsidal lines (i=0.5–1.5d), contiguous laterad of parapsidal line and on anterolateral portion. Mesoscutellum weakly imbricate-tessellate, submedial punctation moderately dense (i=1–1.5d). Axilla punctate. Metanotum imbricate. Preëpisternum rugulose. Hypoepimeral area and mesepisternum rugulose, imbricate posteriorly. Metepisternum with dorsal half rugoso-carinulate, ventral half imbricate. Metapostnotum with weak rugae reaching 2/3 distance to posterior margin, posterior margin imbricate. Propodeum with dorsolateral slope and lateral surface imbricate, posterior surface tessellate. Metasomal terga polished except dorsal portion of declivitous surface coriarious, punctation relatively sparse throughout (i=1–2.5d).

Structure. Head moderately elongate (length/width ratio = 0.98). Eyes convergent below (UOD/LOD ratio = 1.32). Clypeus ½ below suborbital tangent, apicolateral margins weakly convergent. 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 2 branches. Metapostnotum truncate (MMR ratio = 1.43), posterior margin rounded onto posterior surface. Propodeum with oblique carina virtually absent, lateral carina weak, reaching halfway to dorsal margin.

MALE. Unknown,

Range. Florida, topotypical ( Fig. 199 ).

Floral records. ASTERACEAE : Chrysopsis .

Comments. Only known from the holotype. The holotype appears to be somewhat bleached and the colouration listed above may not be reliable.

Figures

FIGURE 197. Lasioglossum stuartense (Mitchell) female, (A) lateral habitus, (B) face. Scale bars = 1 mm.

FIGURE 198. Lasioglossum stuartense (Mitchell) female, dorsal view of mesosoma.

FIGURE 199. Distribution map of Lasioglossum stuartense (square), L. surianae (stars) and L. tamiamense (circles).