Lasioglossum (Dialictus) sedi (Sandhouse)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 294-298

Lasioglossum (Dialictus) sedi (Sandhouse)

( Figures 204A–D , 205A–F )

Halictus (Chloralictus) sedi Sandhouse, 1924: 12 . ♀. Holotype. ♀ USA, Colorado, Boulder , 21.vi., on Sedum stenopetalum, (Cockerell) ; [NMNH: 26401]. Examined.

Taxonomy. Krombein, 1958: Lasioglossum (Chloralictus) sedi , p. 230 (catalogue, tax. status by Timberlake); Hurd, 1979: Dialictus sedi , p. 1971 (catalogue); Moure & Hurd, 1987: Dialictus sedi , p. 130 (catalogue).

Diagnosis. Females of L. sedi can be recognised by the diagnostic combination of a moderately elongate head (length/width ratio = 1.00–1.03), weakly lineolate gena, dense mesoscutal punctures except submedially (i=1–1.5d), minute mesepisternal punctures densely spaced ( Fig. 35B ), metapostnotum rugoso-striate except posterior margin smooth, T1 declivitous surface coriarious on ventral portion ( Figs. 32B , 204D ), and distinctly green metasomal terga. They are very similar to L. prasinogaster , L. sandhousiellum and the American species L. veganum (Cockerell) . Female L. prasinogaster have very distinct and relatively strong mesepisternal punctures ( Fig. 35A ). Female L. sandhousiellum have the T1 declivitous surface polished on the ventral portion due to lack of microsculpture ( Fig. 32A ). Female L. veganum have the gena lineolate.

Males of L. sedi can be recognised by the moderately elongate head (length/width ratio = 0.99–1.00), facial tomentum limited to lower paraocular area, flagellomeres moderately short (length/width ratio = 1.27– 1.50) with the ventral surface brownish yellow, deep mesoscutal punctures moderately sparse on central disc (i=1–2d), hypoepimeral area and mesepisternum polished due to lack of microsculpture with deep punctures (i≤d), subhyaline wings with reddish brown pterostigma, tarsi brown, and metasomal terga distinctly punctate except apical impressed areas impunctate. They are similar to L. sandhousiellum and L. prasinogaster . Male L. sandhousiellum have pale brownish yellow tarsi and sparse punctures on posterior half of central disc (i=1– 4d). Male L. prasinogaster have more abundant pubescence on the face and mesosoma, hyaline wings with pale pterostigma and very dense mesepisternal punctures (i<d).

Redescription. FEMALE. Length 5.00– 5.37 mm; head length 1.42–1.61 mm; head width 1.39–1.58 mm; forewing length 3.90–4.21 mm.

Colouration. Head and mesosoma pale green with golden reflections. Clypeus with apical half blackish brown and basal half, and supraclypeal area bronze. Antenna dark brown, F2–F10 with ventral surface reddish brown to brownish yellow. Mesepisternum and metapostnotum sometimes bluish. Tegula reddish to translucent brownish yellow. Wing membrane subhyaline, venation and pterostigma pale brownish yellow. Legs brown, medio- and distitarsi reddish brown. Metasoma terga green, sterna brown, apical margins pale brownish red to pale translucent yellow.

Pubescence. Dull white. Moderately dense. 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 subappressed pubescence partially obscuring surface. Metepisternum moderately obscured by tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (1.5–2 OD). Metasomal terga with moderately sparse, fine setae. T1 acarinarial fan weak, complete dorsally. T1 with tomentum dorsolaterallly. T2 basolaterally and T3–T5 entirely with tomentum partially obscuring surface. T2 apicolateral and T3–T4 apical margins with sparse fringes.

Surface sculpture. Face imbricate. Clypeus polished, punctation strong (i=1–3d). Supraclypeal area central portion polished, punctation sparse (i=1–3d). Lower paraocular and antennocular areas with punctation dense (i≤1d). Upper paraocular area and frons punctate-reticulate. Ocellocular area reticulate-punctate. Gena weakly lineolate-punctate. Postgena polished. Mesoscutum weakly imbricate, punctation fine, dense between parapsidal lines (i≤1d), moderately dense submedially (i=1–1.5d), very dense laterad and mesad of parapsidal lines (i<d), contiguous on anterolateral portion. Mesoscutellum polished, submedial punctation moderately dense (i=1–1.5d). Preëpisternum weakly reticulate. Hypoepimeral area reticulate-punctate (i=d). Mesepisternum dorsal half reticulate-punctate (i<d), ventral half weakly imbricate, punctation fine (i≤d). Metepisternum with dorsal third rugoso-striate, ventral portion imbricate. Metapostnotum incompletely rugoso-striate, posterior margin imbricate. Propodeum with dorsolateral slope weakly imbricate, lateral surface ruguloso-tessellate, posterior surface imbricate. Metasomal terga polished except T1 declivitous surface and T2–T5 margins weakly coriarious. T1 dorsal surface with punctation moderately dense (i=2–2.5d). T2–T4 punctation on basal halves moderately dense (i=1–1.5d), sparse on apical halves (i=2–3d).

Structure. Head moderately elongate (length/width ratio = 1.00–1.03). Eyes weakly convergent below (UOD/LOD ratio = 1.08–1.12). Clypeus 3/4–4/5 projecting below suborbital line, apicolateral margins strongly convergent. Antennal sockets close (IAD/OAD ratio <0.5). Frontal line carinate, ending 2 OD below median ocellus. OOD greater than IOD. Gena narrower than eye. Inner metatibial spur pectinate 3–4 with teeth. Metapostnotum moderately elongate (MMR ratio = 1.16–1.21), posterior margin rounded onto posterior surface. Propodeum with oblique carina virtually absent, lateral carina weak, reaching halfway to dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.76– 5.00 mm; head length 1.44 mm; head width 1.44–1.45 mm; forewing length 3.60 mm.

Colouration. Flagellum with ventral surface reddish brown to brownish yellow.

Pubescence. Face below eye emargination clothed tomentum, not greatly obscuring surface. Lower paraocular with dense tomentum, obscuring surface. Gena with sparse tomentum. T2–T5 with sparse tomentum. S2–S3 with moderately sparse, erect hairs (1–1.5 OD), S2–S4 apicolateral margins with subappressed hairs.

Surface sculpture. Integument more polished. Mesoscutal punctation between parapsidal lines moderately sparse (i=1–2d). Mesepisternum polished, punctation distinct (i≤d). Propodeum with dorsolateral slope and lateral surface reticulate-punctate (i≤d). Metasomal terga punctation moderately dense (i=1–1.5d), apical impressed areas impunctate.

Structure. Head round (length/width ratio = 0.99–1.00). Eyes convergent below (UOD/LOD ratio = 1.24– 1.27). Clypeus projecting 2/3 below suborbital line, apicolateral margins convergent. Antennal sockets distant (IAD/ AOD ratio = 1.0). OOD greater than IOD. Pedicel greater than F1. F2 length 1.4 F2–F10 moderately short (length/width ratio = 1.27–1.50), Metapostnotum truncate (MMR ratio = 1.44), posterior margin rounded onto posterior surface.

Terminalia . S7 with median lobe weakly clavate, apex rounded ( Fig. 205F ). S8 with apicomedial margin weakly convex ( Fig. 205F ). Genitalia as in Fig. 205D–E . Gonobase with ventral arms widely separated. Gonostylus small. Retrorse lobe elongate, attenuated apically.

Range. British Columbia southeast to Colorado ( Fig. 206 ).

Additional material examined. CANADA: BRITISH COLUMBIA: 2♀ Okanagan-Similkameen Reg. Dist. , Oliver, Ripley Lk., N49.2435 W119.6324, 925 m, 13.vii.2008 (L. R. Best) ; 1♀ Okanagan-Similkameen Reg. Dist. , Summerland, Garnet Lk., N49.6879 W119.7761, 650 m, 18.vii.2008 (L. R. Best) ; USA: COLO-

RADO: 5♀ Larimer Co., N40.6833 W105.3975, 11–12.v.2004 (S.W. Droege) ; 2♀ Jackson Co., N40.6017 W106.0726, 11–12.v.2004 (S.W. Droege); IDAHO : 1♀ N44.39329 W111.38278, 2032 m, 23.vi.2007 (Gibbs & Sheffield); WASHINGTON : 1♀ Okanagan Co., 1.5 mi E Bailey , 11U N5373331 E346958, 28.vi.2004 (L. Wilson) ; 1♀ Okanagan Co., 1.5 mi E Bailey , 11U N5386972 E283581, 3.vii.2004 (J. Wilson) ; 1♀ Okanagan Co., 1 mi E Muckamuck Hill , 11U N5386867 E296155, 4.vii.2004 (J. Wilson & L. Wilson) ; [PCYU].

Floral records. CAMPANULACEAE : Campanula rotundifolia ; CRASSULACEAE : Sedum stenopetalum ; HYDROPHYLLACEAE : Phacelia leptosepala .

Comments. Common. First description of male.

Figures

FIGURE 32. T1 declivitous surface of female (A) L. sandhousiellum, arrows indicated polished surface, (B) L. sedi, arrows indicated coriarious surface.

FIGURE 35. Mesopleuron of female Dialictus (A) moderately coarse, L. prasinogaster, (B) fine, L. sedi.

FIGURE 204. Lasioglossum sedi (Sandhouse). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) T1. Scale bars, A–C = 1 mm.

FIGURE 205. Lasioglossum sedi (Sandhouse). Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) ventral view of genital capsule; (E) dorsal view of genital capsule; (F) S7, S8. Scale bars, A–C = 1 mm, F = 0.5 mm.

FIGURE 206. Distribution of Lasioglossum sedi (medium grey), semicaeruleum (light grey), and L. sheffieldi (dark grey and stars).