Lasioglossum (Dialictus) testaceum (Robertson)

Gibbs, Jason, 2011, Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini), Zootaxa 3073, pp. 1-216 : 197-201

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Lasioglossum (Dialictus) testaceum (Robertson)


Lasioglossum (Dialictus) testaceum (Robertson)

( Figures 213 View FIGURE 213 –217)

Halictus testaceus Robertson, 1897: 323 . Ƥ.

Lectotype. Ƥ 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 . Ƥ. [new synonymy]

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

Halictus (Chloralictus) occultus Sandhouse, 1924: 27 . 3. (primary junior homonym of Halictus occultus Vachal, 1904 ). Holotype. 3 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 3, p. 418, D. testaceus Ƥ, 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 View FIGURE 1 , 28 View FIGURE 28 B), oblique carina strong, metasoma pale brownish yellow ( Fig. 213 View FIGURE 213 A), T 1 acarinarial fan absent ( Fig. 214 View FIGURE 214 ), and T 4 with moderately dense tomentum. Lasioglossum rufulipes are similar but can be distinguished by their reddish brown tegula and metasomal terga ( Fig. 186 View FIGURE 186 A), and T 4 with sparse tomentum.

Male L. testaceum can be distinguished by the following combination: labrum, mandible and distal half of the clypeus ( Fig. 215 View FIGURE 215 B), most of protibia yellow ( Fig. 215 View FIGURE 215 A); mesoscutal punctation sparse between parapsidal lines (i= 1– 2 d) ( Fig. 216 View FIGURE 216 ); mesepisternum finely punctate; gonobase ventral rim entire; and retrorse lobe narrow and paralled-sided (Fig. 217 A). 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, F 3 –F 10 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, T 1 anterolateral portion brown, T 2 – T 4 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. T 1 acarinarial fan absent, declivitous surface with sparse erect hairs (1 OD). T 2 –T 3 basolateral portion with tomentum. T 4 with tomentum across disc, partially obscuring surface. T 2 apicolateral and T 3 –T 4 apical margins with sparse apical fringe.

Surface sculpture. Face imbricate, punctation fine, shallow. Clypeus polished, basal margin weakly imbricate, punctation moderately dense (i= 1–1.5 d). Supraclypeal area with punctation moderately sparse (i= 1–2 d). Lower paraocular area with punctation dense, obscure (i≤d). Antennocular area with punctation moderately dense (i= 1–1.5 d). 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= 1–2 d), dense laterad of parapsidal lines (i≤d), and contiguous on anterolateral portions. Mesoscutellum polished, submedial punctation moderately sparse (i= 1–2 d). Axilla punctate. Metanotum ruguloso-imbricate. Preëpisternum 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= 1.5–2 d), 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. S 2 –S 4 apical halves with sparse, plumose hairs (1–1.5 OD), S 4 –S 5 with simple, posteriorly directed hairs (1.5 OD).

Surface sculpture. Mesoscutellum with submedial punctation sparse (i= 2–5 d). Propodeum with dorsolateral slope and posterior surface rugose. Metasomal terga punctate (i= 2–4 d) 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 1.5 OD from median ocellus. Pedicel subequal to F 1. F 2 length 2.4 X F 1. F 2 –F 10 elongate (length/width ratio = 1.60–2.18). Metapostnotum elongate (MMR = 1.00– 1.08).

Terminalia . S 7 with median lobe long, acuminate, apex narrowly rounded (Fig. 217). S 8 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.

. Lasioglossum testaceum (Robertson) male terminalia , (A) ventral view, (B) dorsal view. Scale bar = 0.5 mm.

Range. British Columbia south to Colorado, east to Illinois ( Fig. 191 View FIGURE 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 Ƥ Edmonton, 19.v. 1986 (D. Blades); 1 Ƥ 233 Red Deer R. At Hwy 876 (W. Of Dinosaur P.P.), 5–6.vii. 1989 (J.H. O’Hara); [ CNC]; 1 Ƥ Edmonton, 25.v. 1986 (D. Blades); 3 ƤƤ Fort Mcleod, Oldman Riv. Cpgd, 1984 (T. Spanton); 1 Ƥ 13 Writing-On-Stone Prov. Park, Birch-North, 18– 25.vii. 1990 (D. McCorquodale); 1 Ƥ Writing-On-Stone Prov. Park, Grass-North, 26.v– 1990 (D. McCorquodale); 2 ƤƤWriting-On-Stone Prov. Park, Sand-North, 18–25.vii. 1990 (D. McCorquodale); 2 ƤƤWriting-On-Stone Prov. Park, Sand-North, 1.viii. 1990 (M. Klassen); 1 Ƥ Writing-On-Stone Prov. Park, Sedge-South, 6– 1990 (D. McCorquodale) 1 Ƥ Writing-On-Stone Prov. Park, Sedge-South, 12– 1990 (D. McCorquodale) 1 Ƥ Writing-On-Stone Prov. Park, Sedge-South, 1990 (M. Klassen); [ PMAE]; BRITISH COLUMBIA: 333 Hedley, 5 mi. S., 24.vii. 1985 (Finnamore & Thormin); [ PMAE]; SASKATCHEWAN: 333 Melfort, 25.viii. 1950 (L.A. Konotopetz); [ CNC]; USA: COLORADO: 1 Ƥ Ridgway, About N 38 ˚ 9 ʹ W 107 ˚ 45 ʹ, 7000 ft., 10.vii. 1919; [ AMNH]; 1 Ƥ Florissant, (Cockerell); [ BMNH]; 1 Ƥ Florissant, Exped. 1906, 1907 (S.A. Rohwer); [ ANSP]; 8 ƤƤ 9333 Teller Co., 7 m N Woodland Pk., South Meadows Camp, 8000 ft., 21–28.vii. 1977 (S. Peck); [ CNC]; 1 Ƥ Gunnison Co., Almont, 24.vii. 1983 (G.C. Eickwort); 1033 Gunnison Co., Almont, 26.vii. 1988 (G.C. Eickwort); [ CUIC]; 1 Ƥ Florissant, Exped. 1906, 1907 (S.A. Rohwer); 1 Ƥ Florissant, Exped. 1906, 1907 (S.A. Rohwer); [ INHS]; 1 Ƥ Florissant, Exped. 1906, 1907 (S.A. Rohwer); [ NMNH]; ILLINOIS: 1 Ƥ Carlinville (C. Robertson); [ CUIC]; NEW MEXICO: 1 Ƥ Trout Springs, 27.iv (Cockerell); [ CUIC]; NORTH DAKOTA: 1 Ƥ Medora, 19.v. 1919 (C.H. Waldron); [ CUIC]; 2 ƤƤ Medora, 19.v. 1919 (C.H. Waldron); [ NMNH]; WYOMING: 30 ƤƤ 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 (2010 b) placed this species in the subgenus Evylaeus (see comments for L. rufulipes above).

Lasioglossum (Dialictus) timothyi Gibbs

Lasioglossum (Dialictus) timothyi Gibbs, 2010: 333 . Ƥ 3.

Holotype. Ƥ CANADA, Ontario, Norfolk Co., Turkey Point Provincial Park, N 42 ° 42.227´W080° 19.877´, 7– 2006 (A. Taylor); [ PCYU].

Diagnosis. Female L. timothyi can be recognised by the following diagnostic combination: head wide (length/width ratio = 0.90–0.93); supraclypeal area noticeably convex; mesoscutal punctation sparse between parapsidal lines (i= 1–3 d); mesepisternum weakly rugose; propodeum with dorsolateral slope rugose, oblique carina strong ( Fig. 25 View FIGURE 25 A); T 1 acarinarial fan without dorsal opening; and brown metasomal terga, apical impressed areas distinctly punctate. They are similar to L. versatum , L. smilacinae , L. cressonii , and L. ceanothi . Female L. versatum have weak oblique carinae and T 1 acarinarial fan open dorsally. Female L. smilacinae have mesepisternum rugulose with distinct punctures ventrally. Female L. cressonii have very strongly rugose mesepisternum and coarse mesoscutal punctures. Female L. ceanothi have weak oblique propodeal carinae and moderately dense mesoscutal punctures (i= 1–1.5 d).

Male L. timothyi can be recognised by the relatively head long (length/width = 0.98); facial tomentum dense only on lower paraocular area; flagellomeres relatively long (length/width ratio = 1.54–1.71); mesoscutum polished due to weak microsculpture, punctures sparse between parapsidal lines (i= 1–3 d); mesepisternum rugose to strongly reticulate-punctate; lateral surface of propodeum rugose; metasomal terga brown, apical impressed areas distinctly punctate; and metasomal sterna with sparse pubescence. They are similar to L. cressonii , which has mesepisternum coarsely rugose.

Range. Manitoba, Ontario east to Maine, south to North Carolina. USA: IL, IN, MA, ME, MI, NC, NY, SD, WI, WV. CANADA: MB, NB, NS, ON.

DNA Barcode. Available. Multiple sequences.

Comments. See Gibbs (2010).


Illinois Natural History Survey


Smithsonian Institution, National Museum of Natural History


Canadian National Collection of Insects, Arachnids, and Nematodes


American Museum of Natural History


Academy of Natural Sciences of Philadelphia


Cornell University Insect Collection


University of Newcastle


The Packer Collection at York University


Department of Natural Resources, Environment, The Arts and Sport














Lasioglossum (Dialictus) testaceum (Robertson)

Gibbs, Jason 2011

Lasioglossum (Chloralictus) sandhouseae

Michener 1951: 1117

Halictus (Chloralictus) occultus

Sandhouse 1924: 27

Halictus (Chloralictus) scrophulariae

Cockerell 1906: 428

Halictus testaceus

Robertson 1897: 323