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Lasioglossum testaceum (Robertson, 1897)
Halictus testaceus Robertson, 1897; Chloralictus testaceus (Robertson, 1897); Dialictus testaceus (Robertson, 1897); Lasioglossum (Evylaeus) testaceum (Robertson, 1897); Halictus (Chloralictus) occultus_homonym Sandhouse, 1924; Lasioglossum (Chloralictus) sandhouseae Michener, 1951, replacement name; Dialictus sandhouseae (Michener, 1951); Lasioglossum (Dialictus) sandhouseae Michener, 1951; Halictus (Chloralictus) scrophulariae Cockerell, 1906; Dialictus scrophulariae (Cockerell, 1906); Lasioglossum (Dialictus) scrophulariae (Cockerell, 1906)

Life   Insecta   Hymenoptera   Apoidea   Halictidae   Lasioglossum
Subgenus: Dialictus

Lasioglossum testaceum FEM mm x f
© Copyright Laurence Packer 2014 · 7
Lasioglossum testaceum FEM mm x f

Click on map for details about points.


Identification Summary: Moderate sized; similar to to L. sandhouseae except abdomen bright orange;rare;told from L. nymphale and L. pictum by the Agapostemon-like raised line around the rear face of the propodeum, this line stopping as it curves around to the top leaving most of the rim open where it smoothly rounds over the edge, in pictum and nymphale this line stops less than half way up the side of the rear face; the mesepisturnum also has almost no pits present; the scutum has pits that are less dense. This appears to be primarily a great plains species. We would be very interested in seeing any specimens!

Extracted from Jason Gibbs. 2011. Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini.) Zootaxa.

Lasioglossum (Dialictus) testaceum (Robertson)

Halictus testaceus Robertson, 1897: 323. ♀.

Lectotype. ♀ USA, Illinois, Macoupin Co., Carlinville, 11.iv.1896 (C. Robertson); [INHS: 17843] by W.E. LaBerge (in Webb 1980). Examined.

Halictus (Chloralictus) scrophulariae Cockerell, 1906: 428. ♀. [new synonymy]

Holotype. ♀ USA, Colorado, Florissant, 25.vii., (Cockerell); [NMNH: 27772]. Examined.

Halictus (Chloralictus) occultus Sandhouse, 1924: 27. ♂. (primary junior homonym of Halictus occultus Vachal, 1904).

Holotype. ♂ USA, Colorado, Florissant, 23.vii., on Potentilla, (Cockerell); [NMNH: 26424]. Examined.

Lasioglossum (Chloralictus) sandhouseae Michener, 1951: 1117. (catalogue: new name for H.(C.) occultus Sandhouse) [new synonymy]

Taxonomy. Robertson, 1902: Chloralictus testaceus, p 249 (key); Michener, 1951: Lasioglossum (Chloralictus) scrophulariae, p. 1117, L. (C.) testaceum, p. 1118 (catalogue); Mitchell, 1960: Dialictus sandhouseae ♂, p. 418, D. testaceus ♀, p. 424 (redescription); Krombein, 1967: Lasioglossum (Dialictus) sandhouseae, p. 466 (catalogue); Hurd, 1979: Dialictus sandhouseae, p. 1971, D. scrophulariae, p. 1971, D. testaceus, p. 1972 (catalogue); Moure & Hurd, 1987: Dialictus sandhouseae, p. 129, D. scrophulariae, p. 129, D. testaceus, p. 135 (catalogue).

Diagnosis. Female L. testaceum can be distinguished from all Lasioglossum North of Mexico by the following diagnostic combination: head and mesosoma metallic, tegula pale, lateral and posterior propodeal surfaces completely separated by strong lateral carina (Figs. 1, 28B), oblique carina strong, metasoma pale brownish yellow (Fig. 213A), T1 acarinarial fan absent (Fig. 214), and T4 with moderately dense tomentum. Lasioglossum rufulipes are similar but can be distinguished by their reddish brown tegula and metasomal terga (Fig. 186A), and T4 with sparse tomentum.

Male L. testaceum can be distinguished by the following combination: labrum, mandible and distal half of the clypeus (Fig. 215B), most of protibia yellow (Fig. 215A); mesoscutal punctation sparse between parapsidal lines (i=1–2d) (Fig. 216); mesepisternum finely punctate; gonobase ventral rim entire; and retrorse lobe narrow and paralled-sided (Fig. 217A). Male L. rufulipes lack mesepisternal punctures.

Redescription. FEMALE. Length 4.45–4.88 mm; head length 1.22–1.38 mm; head width 1.34–1.40 mm; forewing length 3.66–3.97 mm.

Colouration. Head and mesosoma bluish green with reflections. Labrum brownish yellow. Mandible yellow, apex red, mandible brown. Clypeus with apical half reddish brown, basal half, and supraclypeal area bronze. Antenna brown, F3–F10 with ventral surface brownish yellow. Pronotal lobe apex brownish yellow. Tegula yellow-translucent. Wing venation and pterostigma pale, brownish yellow. Wing membrane subhyaline. Legs brown, except tibial bases and apices,protibial inner surface and tarsi brownish yellow. Metasoma pale brownish yellow, T1 anterolateral portion brown, T2–T4 with brown lateral spots.

Pubescence. Dull white. Sparse. Head and mesosoma with moderately dense woolly hairs (1–1.5 OD), longest on genal beard, metanotum, and mesopleuron (2–2.5 OD). Face with sparse subappressed tomentum partially obscuring surface. Gena with sparse tomentum adjacent to eye. Pronotal lobe and dorsolateral angle with dense tomentum. Metepisternum obscured by tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with sparse, fine hairs. T1 acarinarial fan absent, declivitous surface with sparse erect hairs (1 OD). T2–T3 basolateral portion with tomentum. T4 with tomentum across disc, partially obscuring surface. T2 apicolateral and T3–T4 apical margins with sparse apical fringe.

Surface sculpture. Face imbricate, punctation fine, shallow. Clypeus polished, basal margin weakly imbricate, punctation moderately dense (i=1–1.5d). Supraclypeal area with punctation moderately sparse (i=1–2d). Lower paraocular area with punctation dense, obscure (i≤d). Antennocular area with punctation moderately dense (i=1–1.5d). Upper paraocular area and frons punctate-reticulate. Ocellocular area obscurely minutely punctate (i≤d). Gena and postgena lineolate. Mesoscutum weakly imbricate, punctation fine, moderately sparse between parapsidal lines (i=1–2d), dense laterad of parapsidal lines (i≤d), and contiguous on anterolateral portions. Mesoscutellum polished, submedial punctation moderately sparse (i=1–2d). Axilla punctate. Metanotum ruguloso-imbricate. Preλpisternum rugulose. Hypoepimeral area obscurely punctate. Mesepisternum below imbricate. Metepisternum with upper third rugoso-carinulate and lower portion imbricate. Metapostnotum incompletely, anastomosing rugose. Propodeum dorsolateral slope, lateral and posterior surfaces imbricate. Metasomal terga polished, apical impressed areas weakly imbricate, punctation on basal half fine (i=1.5–2d), on apical half obscure, virtually impunctate (except along premarginal line).

Structure. Head wide (length/width ratio = 0.91–0.92). Eyes weakly convergent below (UOD/LOD ratio = 1.15–1.17). Clypeus ½ below suborbital tangent, apicolateral margins strongly convergent. Antennal sockets moderately distant(IAD/OAD > 0.6). Frontal carina ends 2 OD from median ocellus. IOD greater than OOD. Gena narrower than eye. Hypostomal carinae parallel. Pronotum with dorsolateral angle obtuse. Pronotal ridge broadly rounded, interrupted by oblique sulcus. Mesoscutum with anteromedial margin very weakly emarginate. Tegula ovoid. Procoxa and protrochanter unmodified. Inner metatibial spur pectinate with 4–5 short, narrow branches (not including apex of rachis). Metapostnotum lunate, elongate (MMR = 1.08–1.13), posterior margin narrowly rounded onto posterior surface. Propodeum strongly carinate with dorsolateral slope steeply angled, lateral carina reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length. 4.64–5.25 mm; head length 1.27–1.38 mm; head width 1.30–1.40 mm; forewing length 3.60–3.81 mm.

Colouration. Labrum, mandible, and apical half of clypeus pale yellow. Flagellum with ventral surface orange-yellow. Legs brown, except tibiae and tarsi yellow, anterior and posterior surfaces of tibiae infused with brown. Metasoma reddish brown, apical impressed areas often yellowish brown.

Pubescence. Face below eye emargination with dense tomentum, less dense on clypeus. S2–S4 apical halves with sparse, plumose hairs (1–1.5 OD), S4–S5 with simple, posteriorly directed hairs (1.5 OD).

Surface sculpture. Mesoscutellum with submedial punctation sparse (i=2–5d). Propodeum with dorsolateral slope and posterior surface rugose. Metasomal terga punctate (i=2–4d) except apical impressed areas impunctate.

Structure. Head moderately wide (length/width ratio = 0.94–0.98). Eyes convergent below (UOD/LOD ratio = 1.43–1.50). Antennal sockets distant (IAD/OAD > 1.75). Frontal carina ends 1.5OD from median ocellus. Pedicel subequal to F1. F2 length 2.4X F1. F2–F10 elongate (length/width ratio = 1.60–2.18). Metapostnotum elongate (MMR = 1.00–1.08).

Terminalia. S7 with median lobe long, acuminate, apex narrowly rounded (Fig. 217). S8 with apical margin weakly convex (Fig. 217). Genital capsule as in Fig. 217. Gonobase with ventral arms connected. Gonostylus small, covered with fine hairs, dorsal setae elongate. Retrorse lobe narrow, parallel-sided, covered with fine hairs. Penis valve narrow apically.

Range. British Columbia south to Colorado, east to Illinois (Fig. 191). Recorded, probably erroneously, from North Carolina and Delaware (Moure & Hurd 1987). USA: CO, ID, IL, ND, NM, UT. CANADA: AB, BC, SK.

Additional material examined. CANADA: ALBERTA: 1♀ Edmonton, 19.v.1986 (D. Blades); 1♀2♂♂ Red Deer R. At Hwy 876 (W. Of Dinosaur P.P.), 5–6.vii.1989 (J.H. O’Hara); [CNC]; 1♀ Edmonton, 25.v.1986 (D. Blades); 3♀♀ Fort Mcleod, Oldman Riv. Cpgd, 14.vi.1984 (T. Spanton); 1♀1♂ Writing-On-Stone Prov. Park, Birch-North, 18– 25.vii.1990 (D. McCorquodale); 1♀ Writing-On-Stone Prov. Park, Grass-North, 26.v–25.vi.1990 (D. McCorquodale); 2♀♀Writing-On-Stone Prov. Park, Sand-North, 18–25.vii.1990 (D. McCorquodale); 2♀♀Writing-On-Stone Prov. Park, Sand-North, 1.viii.1990 (M. Klassen); 1♀ Writing-On-Stone Prov. Park, Sedge-South, 6–12.vi.1990 (D. McCorquodale) 1♀ Writing-On-Stone Prov. Park, Sedge-South, 12–20.vi.1990 (D. McCorquodale) 1♀ Writing-On-Stone Prov. Park, Sedge-South, 30.vi.1990 (M. Klassen); [PMAE]; BRITISH COLUMBIA: 3♂♂ Hedley, 5 mi. S., 24.vii.1985 (Finnamore & Thormin); [PMAE]; SASKATCHEWAN: 3♂♂ Melfort, 25.viii.1950 (L.A. Konotopetz); [CNC]; USA: COLORADO: 1♀ Ridgway, About N38°9′ W107°45′, 7000 ft., 10.vii.1919; [AMNH]; 1♀ Florissant, 19.vi (Cockerell); [BMNH]; 1♀ Florissant, Exped. 1906, 1.vi.1907 (S.A. Rohwer); [ANSP]; 8♀♀ 93♂♂ Teller Co., 7 m N Woodland Pk., South Meadows Camp, 8000 ft., 21–28.vii.1977 (S. Peck); [CNC]; 1♀ Gunnison Co., Almont, 24.vii.1983 (G.C. Eickwort); 10♂♂ Gunnison Co., Almont, 26.vii.1988 (G.C. Eickwort); [CUIC]; 1♀ Florissant, Exped. 1906, 2.vi.1907 (S.A. Rohwer); 1♀ Florissant, Exped. 1906, 16.vi.1907 (S.A. Rohwer); [INHS]; 1♀ Florissant, Exped. 1906, 1.vi.1907 (S.A. Rohwer); [NMNH]; ILLINOIS: 1♀ Carlinville (C. Robertson); [CUIC]; NEW MEXICO: 1♀ Trout Springs, 27.iv (Cockerell); [CUIC]; NORTH DAKOTA: 1♀ Medora, 19.v.1919 (C.H. Waldron); [CUIC]; 2♀♀ Medora, 19.v.1919 (C.H. Waldron); [NMNH]; WYOMING: 30♀♀ Laramie, 30.v.1968 (D.W. Ribble); [INHS].

Floral records. ASCLEPIADACEAE: Asclepias speciosa; ASTERACEAE: Nothocalais cuspidata, Taraxacum; FABACEAE: Amorpha canescens, Glycine max; POLYGONACEAE: Eriogonum annuum; SALICACEAE: Salix brachycarpa, S. cordata.

Comments. Uncommon. Rarely collected east of the Mississippi.

The name L. sandhouseae is a replacement for Halictus (Chloralictus) occultus Sandhouse (1924), which is preoccupied by Halictus occultus Vachal (1904) (now L. (Evylaeus) occultum). The epithet sandhouseae has been incorrectly associated with L. rufulipes in the past (Knerer & Atwood 1964). Gibbs (2010b) placed this species in the subgenus Evylaeus (see comments for L. rufulipes above).

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Updated: 2019-10-16 06:56:18 gmt
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