Lasioglossum (Dialictus) michiganense (Mitchell)

Gibbs, Jason, 2010, Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini) 2591, Zootaxa 2591 (1), pp. 1-382 : 191-194

Lasioglossum (Dialictus) michiganense (Mitchell)

( Figures 144A–D , 145A–E )

Paralictus michiganensis Mitchell, 1960: 448 . ♀. Holotype. ♀ USA, Michigan, Wayne Co., 2.vi.1940, [NCSU]. Examined.

Taxonomy. Krombein, 1967: Lasioglossum (Paralictus) michiganense , p. 467; (catalogue); Hurd, 1979: Paralictus michiganensis , p. 1974 (catalogue); Moure & Hurd, 1987: Paralictus michiganensis , p. 143 (catalogue).

Diagnosis. For females see diagnosis for L. asteris .

Males of L. michiganense may be recognised by the diagnostic combination of the pronotum strongly striate, mesoscutum faintly polished due to weak microsculpture, mesoscutal punctures fine, and very sparse hairs on the metasomal sterna. They are most similar to L. mitchelli which have the pronotum imbricate.

Redescription. FEMALE. Length 5.12–5.98 mm; head length 1.51–1.54 mm; head width 1.75–1.80 mm; forewing length 4.33–4.45 mm.

Colouration. Head and mesosoma purplish metallic, mesepisternum with green reflections. Clypeus apical portion blackish brown. Antenna dark brown, flagellum with venral surface reddish brown. Tegula reddish brown. Wing membrane subhyaline, venation and pterostigma reddish amber. Legs brown, tarsi reddish brown-brownish yellow. Metasoma blackish brown, terga and sterna margins translucent reddish to yellowish brown.

Pubescence. Dull white. Sparse. Head and mesosoma with moderately dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum and mesopleuron (1.5–2 OD). Face without appressed hairs. Clypeus distal margin with long bristles (2–3 OD). Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (1.5–2 OD). Mesofemoral and mesotibial combs present but sparse relative to non-parasites. Femoral scopa greatly reduced, only a few long, curved hairs remain. Penicillus reduced relative to non-parasites. Metasomal terga with sparse, fine setae and no tomentum. T1 acarinarial fan with wide dorsal opening. T2–T3 apicolateral and T4 apical margins with very sparse fringes. Metasomal sterna with sparse posteriorly curved hairs (2–3 OD).

Surface sculpture. Face imbricate, punctation fine, shallow. Clypeus with apical half polished, punctation moderately sparse (i=1–3d). Supraclypeal area with punctation dense (i≤d). 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 punctate (i=1–1.5d). Gena lineolate. Postgena imbricate. Mesoscutum weakly imbricate, punctation fine, shallow, moderately sparse between parapsidal lines (i=1–2d), dense laterad of parapsidal lines (i≤d), contiguous on anterolateral portions. Mesoscutellum similar to mesoscutum, submedial punctation sparse (i=3–6d). Axilla punctate. Metanotum imbricate. Preëpisternum rugulose above, imbricate below. Hypoepimeral area imbricate, obscurely punctate. Mesepisternum vertically striate, obscurely punctate. Metepisternum with dorsal third striate, ventral portion imbricate. Metapostnotum with complete anastomosing rugae. Propodeum with lateral surface obliquely striate, posterior surface imbricate. Metasomal terga weakly coriarious, punctation on basal halves moderately sparse (i=2–3d), sparse on apical halves (i=2–4d).

Structure. Head very wide (length/width ratio = 0.84–0.85). Eyes weakly convergent below (UOD/LOD ratio = 1.06–1.12). Labrum enlarged and flattened, apical process without dorsal keel. Mandible large with distinct subapical tooth. Clypeus 1/3 below suborbital tangent, apicolateral margins convergent. Antennal sockets moderately close (IAD/OAD = 0.6). Frontal line carinate, ending 2 OD below median ocellus. IOD subequal to OOD. Gena wider than, or subequal to, eye. Pronotal dorsolateral angle orthogonal. Basitibial plate lower carina present. Inner metatibial spur pectinate with 4–5 teeth. Metapostnotum truncate (MMR ratio = 1.33–1.52), posterior margin sharply angled onto posterior surface. Propodeum with oblique carina virtually absent, lateral carina weak, not reaching dorsal margin. T5 medial specialized area reduced.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.43– 6.10 mm; head length 1.44–1.46 mm; head width 1.49–1.51 mm; forewing length 3.97–4.00 mm.

Colouration. Flagellum with ventral surface orange-yellow. Tibial bases and tarsi brownish yellow.

Pubescence. Face below eye emargination with sparse tomentum not obscuring surface. Lower paraocular area with dense tomentum obscuring surface. Gena without tomentum. S2–S3 apical portions with sparse hairs (1 OD).

Surface sculpture. Clypeal punctation moderately dense (i=1–2d). Pronotum coarsely striate. Metanotum rugose. Mesepisternum anterior portion weakly rugulose, posterior portion minutely punctate (i=1–1.5d). Metasomal terga with punctation on basal halves moderately sparse (i=1.5–2d), apical halves impunctate (except along premarginal line).

Structure. Head moderately wide (length/width ratio = 0.97). Eyes strongly convergent below (UOD/LOD ratio = 1.43–1.48). Clypeus 2/3 below suborbital tangent, apicolateral margins weakly convergent. Antennal sockets distant (IAD/OAD> 1.3). Frontal line carinate, ending 1.5 OD below median ocellus. Pedicel shorter than F1. F2 length 1.6–1.7X F1. F2–F10 moderately elongate (length/width ratio = 1.58–1.83). Pronotal dorsolateral angle obtuse. Pronotal ridge strongly angled, weakly interrupted by oblique sulcus. Metapostnotum moderately elongate (MMR ratio = 1.33–1.40), posterior margin weakly angled onto posterior surface.

Terminalia . S7 with median lobe strongly clavate, apex rounded ( Fig. 145D ). S8 with apicomedial margin weakly convex ( Fig. 145D ). Genitalia as in Fig. 145D–E . Gonobase with ventral arms widely separated. Gonostylus small, dorsal setae elongate. Retrorse lobe elongate, weakly attenuated, recurved apically.

Range. Southern Ontario south to North Carolina, west to Wisconsin ( Fig. 143 ).

Additional material examined. CANADA: ONTARIO: 1♂ Brock , 24.ix.2003 ; 1♀ Toronto, York University , N43.77175 W079.4965, 3.x.2006 (H. Ngo); [ PCYU] ; USA: DISTRICT OF COLUMBIA: 1♀ Washington, N38.89138 W077.02416, 18–19.x.2004 (E. Keto) ; NORTH CAROLINA: 1♂ Grandfather Mtn. , N36.08942 W081.83699, 13viii.2006 (J. Gibbs); [ PCYU] .

Comments. Rare. This is a parasitic species. First description of male.

Figures

FIGURE 143. Distribution of Lasioglossum marinense (medium grey), L. michiganense (dark grey), and L. mitchelli (light grey).

FIGURE 144. Lasioglossum michiganense (Mitchell). Female (A) lateral habitus; (B) dorsal habitus; (C) face; (D) mandible. Scale bars, A–C = 1 mm.

FIGURE 145. Lasioglossum michiganense (Mitchell). Male (A) lateral habitus; (B) dorsal habitus; (C) face; (D) ventral view of genital capsule, S7, S8; (E) dorsal view of genital capsule. Scale bars, A–C = 1 mm.