Lasioglossum (Dialictus) semicaeruleum (Cockerell)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 298-301

Lasioglossum (Dialictus) semicaeruleum (Cockerell)

( Figures 207A–E , 208A–F )

Halictus semicaeruleus Cockerell, 1895: 66 . ♀.

Holotype. ♀ USA, New Mexico, Santa Fé , 20.vi.1894 (Cockerell), [ NMNH: 27774]. Examined.

Halictus pruinosiformis Crawford, 1906: 284 . ♀ ♂. [new synonymy]

Holotype. ♀ USA, Texas, Fedor , 8.iii.1902, [ NMNH: 12069]. Examined.

Halictus glaucovirens Cockerell, 1919: 290 . ♀.

Holotype. ♀ USA, Colorado, Longs Peak Trail , 20.vii., (Cockerell), [ CAS 15607]. Examined.

Halictus (Chloralictus) exalbidus Sandhouse, 1924: 24 . ♂.

Holotype. ♂ USA, New Mexico, Santa Fe, August , (Cockerell), [ NMNH: 26420]. Examined.

Halictus (Chloralictus) actuarius Sandhouse, 1924: 25 . ♂. [new synonymy]

Holotype. ♂ USA, Colorado, 31.vii.1908, (S.A. Rohwer), [ NMNH: 26421]. Examined.

Taxonomy. Sandhouse, 1924: Halictus (Chloralictus) semicoeruleus , p. 2 (lapsus calami) Cockerell, 1937a: Halictus pruniosiformis , p. 114 (lapsus calami); Michener, 1951: Lasioglossum (Chloralictus) actuarium , p. 1111, L. (C.) pruinosiforme , p. 1116, L. (C.) semicaeruleum , p. 1117 (catalogue, synonymy); Hurd, 1979: Dialictus actuarius , p. 1963, D. pruinosiformis , p. 1970, D. semicaeruleus , p. 1971 (catalogue); Moure & Hurd, 1987: Dialictus actuarius , p. 87, D. pruinosiformis , p. 125, D. semicaeruleus , p. 130 (catalogue).

Diagnosis. Females of L. semicaeruleum can be recognised by diagnostic combination of a wide head (length/width ratio = 0.94–0.97), coarse mesoscutal punctures that are moderately dense on central disc (i=1– 2d), coarse mesepisternal punctures ( Fig. 207D ), hyaline wings with pale venation and pterostigma, strong anastomosing rugae on metapostnotum ( Fig. 207E ), blue or green metasomal terga with apical margins brownish yellow, strong T1 acarinarial fan, and T3–T4 with abundant white tomentum.

Males of L. semicaeruleum are similar to females but can be further distinguished by the weakly convergent eyes (UOD/LOD ratio = 1.08–1.11), moderately elongate flagellomeres (length/width ratio = 1.50–1.55), bright yellow ventrally, more widely spaced mesoscutal punctures (i=1–2.5d), tarsi brownish yellow, and dense and distinct punctures on apical impressed areas of the metasomal terga. They are similar to L. albohirtum and L. prasinogaster . Male L. albohirtum have fine punctures on the mesosoma and sparse punctures on the apical impressed areas of the metasomal terga. Male L. prasinogaster have the posterior half of the metapostnotum smooth and obscure punctures on the apical impressed areas of the metasomal terga.

Redescription. FEMALE. Length 5.55–6.16 mm; head length 1.51–1.58 mm; head width 1.56–1.63 mm; forewing length 3.60–4.70 mm.

Colouration. Head and mesosoma pale green with golden reflections to greenish blue. Clypeus with apical half blackish brown and basal half, and supraclypeal area golden to brassy. Antenna dark brown, flagellum with ventral surface reddish to brownish yellow. Tegula reddish to pale amber. Wing membrane hyaline, venation and pterostigma pale yellow. Legs brown, medio- and distitarsi reddish brown. Metasomal terga pale green to blue, sterna brown, apical margins translucent brownish yellow.

Pubescence. White. Moderately dense. Head and mesosoma with dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum and mesopleuron (2–2.5 OD). Paraocular area with subappressed tomentum. Gena with dense tomentum, obscuring surface near eye. 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 dense, complete dorsally, reaching upper margin of declivitous surface. T1 dorsolateral portion with sparse tomentum. T2 basolaterally and T3–T5 entirely with tomentum obscuring surface. T2 apicolateral and T3–T4 apical margins with very sparse hair bands.

Surface sculpture. Face polished, weakly imbricate, punctation strong. Clypeus polished, weakly imbricate, (i=1–2d), distal portion virtually impunctate. Supraclypeal area with punctation unevenly spaced (i=1– 3d). 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 densely, minutely punctate (i≤d). Gena and postgena polished. Mesoscutum polished, imbricate anteromedially, punctation coarse, moderately dense between parapsidal lines (i=1–2d), dense laterad of parapsidal lines (i≤d) and contiguous to reticulate on anterolateral portions. Mesoscutellum similar to mesoscutum, submedial punctation sparse (i=1–3d). Axilla punctate. Metanotum weakly rugulose. Preëpisternum reticulate. Hypoepimeral area reticulate-punctate. Mesepisternum coarsely punctate (i<d). Metepisternum with dorsal third ruguloso-striate, ventral portion weakly reticulate. Metapostnotum strongly, anastomosingly rugose, nearly reaching posterior margin, posterior margin imbricate. Propodeum with dorsolateral slope rugulose, lateral and posterior surfaces imbricaterugulose. Metasomal terga polished except T1 declivitous surface imbricate, punctation distinct throughout (i=1–2d).

Structure. Head wide (length/width ratio = 0.94–0.97). Eyes weakly convergent below (UOD/LOD ratio = 1.08–1.11). Clypeus below 2/3 suborbital tangent, apicolateral margins strongly 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 teeth. Metapostnotum elongate (MMR ratio = 1.07–1.08). Propodeum with oblique carina very weak, lateral carina short, not reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.21– 4.64 mm; head length 1.37–1.42 mm; head width 1.34–1.39 mm; forewing length 3.72–3.84 mm.

Colouration. Flagellum with ventral surface bright yellow to brownish yellow. Tegula pale amber. Wing membrane hyaline, venation and pterostigma pale yellow. Tibial bases and apices, and tarsi yellow to brownish yellow.

Pubescence. White. Dense. Clypeus, supraclypeal area, paraocular area, and frons ventral half with dense tomentum, obscuring most of lower face. T2–T4 with sparse, basolateral tomentum. S2–S4 with subappressed woolly, erect hairs (2–2.5 OD).

Surface sculpture. Mesoscutal punctation moderately sparse between parapsidal lines (i=1–2.5d). Metanotum polished, distinctly punctate (i=1–2d). Preëpisternum reticulate-punctate. Metepisternum reticulate. Propodeum with dorsolateral slope and lateral and posterior surfaces punctate coarse, irregularly spaced (i=0.5–2d).

Structure. Head round (length/width ratio = 0.98–1.02). Eyes convergent below (UOD/LOD ratio = 1.23– 1.27). Antennal sockets close (IAD/OAD> 1.0). Pedicel subequal to F1. F2 length 1.7–2.0 time F1. F2–F10 moderately elongate (length/width ratio = 1.50–1.55). Metapostnotum elongate (MMR ratio = 1.04–1.13), posterior margin rounded onto posterior surface.

Terminalia . S7 with median lobe elongate, slender, clavate, apex rounded ( Fig. 208E ). S8 with apicomedial margin strongly convex ( Fig. 208E ). Genitalia as in Fig. 208E–F . Gonobase with ventral rim narrowly separated. Gonostylus large. Retrorse lobe wide, short.

Range. Manitoba south to Arizona and Texas, west to California ( Fig. 206 ).

Additional material examined. CANADA: ALBERTA: 1♀ Writing-On-Stone P.P., 24–20.viii.1990 (M. Klassen) ; 1♂ Writing-On-Stone P.P., 10–20.ix.1990 (M. Klassen); [ PMAE] ; MANITOBA: 14♀ 10 km W of Morden , N49.19587 W098.2503, 410 m, 12.vi.2007 (Goulet & Boudreault) ; 1♀ YellowQuill Mxd., Grass Prairie Preserve, near Treesbank , N49°40´51´´ W099°33´16´´, 28.vi.2005 (A.M. Patenaude) ; 1♀ YellowQuill Mxd., Grass Prairie Preserve, near Treesbank , N49°40´51´´ W099°33´16´´, 5.ix.2005 (A.M. Patenaude) ; 1♀ YellowQuill Mxd., Grass Prairie Preserve, near Treesbank , N49°41´28´´ W099°34´29´´, 20.ix.2005 (A.M. Patenaude) ; SASKATCHEWAN: 1♀ Rock Glen , 3.vii.1955 (C.D. Miller); [ CNC] ; USA: ARIZONA: 1♀ Cochise Co., 4 mi E of Wilcox , 1.ix.2004 (L. Packer) ; 1♂ Cochise Co., San Bernardino NWR , N31°20´14´´ W109°13´52´´, 3.v.2001 ( R.L. Minckley) ; 1♀ Portal , viii.2005 (L. Packer) ; 2♀ Willcox , viii.2005 (L. Packer) ; COLORADO: 1♀ Boulder Co., N40°5´45.8´´ W105°16´45.9´´, 8.vi.2004, (Kearns & Oliveras) ; 1♀ Boulder Co., N40°4´15.8´´ W105°17´10.1´´, 1.vi.2005, (Kearns & Oliveras) ; 4♀ Jefferson Co., N39.731 W105.244, 21.viii.2001 (S.W. Droege) ; 52♀ Larimer Co., N40.6639 W105.1894, 11–12.v.2004 (S.W. Droege) ; 1♀ Larimer Co., N40.6833 W105.3975, 11–12.v.2004 (S.W. Droege) ; MINNESOTA: 1♀ Douglas Co., N45.86154 W095.6833, 16.vii.2004 (S. Pimm & S. Wagenius) ; 1♀ Douglas Co., N45.81774 W095.70253, 21.vii.2004 (S. Pimm & S. Wagenius) ; 1♀ Douglas Co., N45.81774 W095.70253, 26.vii.2004 (S. Pimm & S. Wagenius) ; NEW MEXICO: 1♀ Hidalgo Co., 16 mi S of Animas , 23.viii.2007 (J.J. Gibbs) ; 9♂♂ Hidalgo Co., 24.5 mi S of Animas , 23.viii.2007 (J.J. Gibbs) ; TEXAS: 18♀ Denton Co., N33.2043 W097.0816, 27.iv.[2002] (H.W. Ikerd) ; UTAH: 2♀ Washington Co., 0.28 mi NNE Speedlove Kn. , 12S N4134716 E313457, 13.vi.2006 (B. Hays & F. Nicklen) ; 1♀ Washington Co., 0.4 mi NE Speedlove Kn. , 12S N4134751 E313691, 29.v.2006 (B. Hays & F. Nicklen); [ PCYU] .

Floral records. ASTERACEAE : Helianthus annuus , H. petiolaris , Pectis papposa , BERBERIDACEAE : “ Odostemon ”, CACTACEAE : Carnegiea gigantea , CAPPARACEAE : Cleome serrulata , FABACEAE : Dalea candida oligophylla , Parkinsonia microphylla , LOASACEAE : Mentzelia pumila , PAPAVERACEAE : Argemone pinnatifida , POLEMONIACEAE : Polemonium , SCROPHULARIACEAE : Penstemon linarioides coloradoensis , ZYGOPHYLLACEAE : Larrea tridentata .

Comments. Abundant. This species has usually been referred to as L. pruinosiforme . Comparison of the holotypes clearly supports treating that name as a junior synonym of L. semicaeruleum . Two specimens from Maryland, possibly mislabelled, have been seen.

Figures

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

FIGURE 207. Lasioglossum semicaeruleum (Sandhouse). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) mesoscutum; (E) metapostnotum. Scale bars, A–C = 1 mm.

FIGURE 208. Lasioglossum semicaeruleum (Sandhouse). Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) metapostnotum; (E) ventral view of genital capsule, S7, S8; (F) dorsal view of genital capsule. Scale bars, A–C = 1 mm, F = 0.5 mm.