Identification Summary: Very large; abdomen completely black and with only a very few scattered long hairs; thorax very dark greenish blue, so dark that it initially appears black; mesepisturnum glossy, smooth, and with a clear set of obvious pits.
Reprinted with permission from: Mitchell, T.B. 1960 Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 141.
FEMALE—Length 7 mm.; head and thorax pale green laterally, darker above, abdomen blackish; pubescence very short and thin, entirely yellowish-white; head slightly broader than long; clypeus broadly convex, projecting about one-third below suborbital line; supraclypeal area broader than long, much shorter than clypeus; eyes only very slightly convergent below; lateral ocelli subequally distant from eyes and each other; cheeks much broader than eyes, somewhat swollen; face below ocelli rather dull, punctures deep, distinct, rather coarse and quite close, becoming minute and quite sparse on shining vertex; cheeks rather dull posteriorly above, punctures exceedingly minute and obscure, becoming shining below, with very widely scattered, minute punctures, hypostomal carinae very slightly diverging to the broadly rounded apical angle; lower half of face shining, punctures widely scattered, rather coarse on each side of antennae, but becoming sparse and minute below; supraclypeal area dull, with fine and rather sparse punctures, those on upper margin of clypeus deep and distinct, but rather fine and close, becoming sparse, coarse and deep toward apical margin; scutum and scutellum somewhat shining, punctures much as in unicus, (fig. 99), but closer between notaulices and tegulae; pleura shining, punctures variable, but quite deep and distinct, rather coarse anteriorly, becoming minute and obscure posteriorly; dorsal area of propodeum rather incompletely and irregularly striate medially, striae becoming coarse, distinct and complete laterally, lateral surfaces somewhat shining and finely roughened; wings faintly brownish, veins and stigma reddish-testaceous; tegulae piceous, becoming hyaline along rims; legs piceous, becoming somewhat reddened toward extreme apex; abdominal terga somewhat shining, punctures minute and obscure, rather close across base of tergum 2, but becoming sparse and scattered on all the terga apically, apical margins rather broadly impressed, but entirely dark, pale tomentum entirely lacking.
MALE—Length 7 mm.; head and thorax greenish laterally, darker above, abdomen piceous; pubescence short and thin, entirely pale, somewhat more copious on face and on thorax laterally; head somewhat broader than long; clypeus rather narrow, strongly convex, projecting about one-half below suborbital line; eyes strongly convergent below; lateral ocelli very slightly nearer eyes than to each other; antennae somewhat nearer eyes than to each other, basal segment of flagellum about as broad as long, slightly broader and longer than pedicel, following segments nearly twice this length, dark ferruginous beneath, piceous above; mandibles and labrum dark; cheeks slightly narrower than eyes; face below ocelli dull, punctures densely crowded, becoming minute and rather widely separated on shining vertex; cheeks above shining, obscurely and minutely punctate, becoming very finely striate below; hypostomal carinae subparallel; lower half of face more shining, punctures deep and distinct, well separated but not sparse, those on supraclypeal area very fine, well separated, those on clypeus fine and rather close above, becoming more widely separated and somewhat more deep and distinct toward apical margin; scutum and scutellum somewhat shining, punctures rather sparse and variable in size, becoming slightly closer at extreme sides; pleura shining, punctures quite deep, coarse and distinct anteriorly above, but becoming obscure and minute posteriorly; dorsal area of propodeum rather regularly and coarsely striate, lateral surfaces dull, very finely rugoso-striate; wings faintly brownish, veins and stigma brownish-testaceous; tegulae piceous, rims yellowish-hyaline; basal portions of legs piceous, tarsi more or less reddened; abdominal terga somewhat shining, punctures minute, rather evenly and closely distributed across basal portions of discs, becoming more sparse and widely scattered apically, apical margins rather evenly impressed, slightly reddened, pale tomentum entirely lacking; apical margin of sternum 5 very slightly and broadly incurved, median lobe of sternum 7 elongate, slightly narrowed and rounded apically; gonostylus of armature as shown (fig. 102), retrorse lobe rather broad, well covered with short and very fine pubescence.
DISTRIBUTION—Minnesota to New Brunswick, south to Georgia; April to October.
FLOWER RECORDS—Aruncus, Barbarea, Plantago, Rubus, Solidago and Taraxacum.
The male of this species is described here for the first time.
Retrieved from: Gibbs, J. 2010. Revision of the metallic species of Lasioglossum (Dialictus)in Canada (Hymenoptera, Halictidae, Halictini). Zootaxa; 2591, 203-207
Halictus nigro-viridis Graenicher, 1910: 233. ♀.
Holotype. ♀ USA, Wisconsin, Swiss, Burnett Co., 27.vii.1909, [Milwaukee: 32837]
Halictus (Chloralictus) richardsoni Cockerell, 1937a: 113. ♀. [new synonymy]
Holotype. ♀ Canada, Alberta, Wabamun, 60 miles E of Edmonton, 1.vii.1935 (E.H. Strickland); [CNC: 4169].
Dialictus nigroviridis Knerer and Atwood, 1962: 169 (Emend.)
Taxonomy. Cockerell, 1937a: Halictus (Chloralictus) nigroviridis, p. 113 (diagnosis); Michener, 1951: Lasioglossum
(Chloralictus) nigro-viride, p. 1115, L. (C.) richardsoni, p. 1117 (catalogue); Mitchell, 1960: Dialictus nigro-viridis ♀♂, p. 406 (redescription); Krombein, 1967: Lasioglossum (Dialictus) nigroviride, p. 464
(catalogue); Hurd, 1979: Dialictus nigroviridis, p. 1968, D. richardsoni, p. 1971 (catalogue); Moure & Hurd,
1987: Dialictus nigroviridis, p. 115, D. richardsoni, p. 127 (catalogue).
Diagnosis. Females of L. nigroviride can be recognised by diagnostic combination of their large size (7.0–
8.1 mm), golden head and mesosoma, gena wider than eye, sparse mesoscutal punctures on central disc (i=1–
4d), distinct, widely spaced mesepisternal punctures (i=1–2.5d) (Fig. 151D), moderately strong propodeal carinae
and blackish brown metasomal terga that lack any tomentum, fringe hairs and have virtually no fine
setae. They are superficially similar to L. obscurum which are smaller (4.9–5.9 mm) and have weak propodeal
carinae and sparse but distinct fringe hairs on the metasomal terga.
Males of L. nigroviride can be recognised by their large size (7.0–7.5 mm), golden green head and mesosoma,
elongate flagellomeres (length/width ratio = 1.60–1.87), polished mesoscutum due to weak microsculpture
with sparse punctures on central disc (i=1–4d), distinct mesepisternal punctures, blackish brown
metasoma and very dense plumose hairs on S3 and apicolateral portions of S4. Male L. obscurum have relatively
sparse hairs on the metasomal sterna.
Redescription. FEMALE. Length 7.00–8.10 mm; head length 1.82–1.99 mm; head width 1.94–2.11 mm;
forewing length 5.31–5.92 mm.
Colouration. Head and mesosoma metallic gold with green and bluish reflections. Clypeus with apical 2/3
blackish brown. Antenna blackish brown, flagellum with ventral surface brown. Tegula dark reddish brown.
Wing membrane dusky, venation and pterostigma dark amber. Legs dark brown, medio- and distitarsi reddish
browm. Metasomal terga blackish brown, terga and sterna with apical margins reddish brown.
Pubescence. Dull white. Very 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 and gena without subappressed
hairs. Propodeum with moderately sparse plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal
terga with virtually no fine setae. T1 acarinarial fan complete, dorsally very weak. Metasomal terga
without appressed tomentum.
Surface sculpture. Face imbricate, punctation fine. Clypeus polished, punctation sparse (i=1–3d). Supraclypeal
area with punctation sparse (i=1–3d). Lower paraocular and antennocular areas with punctation sparse
(i=0.5–3d). Upper paraocular area punctation dense (i≤d). Frons punctate-reticulate. Ocellocular area distinctly
punctate (i=1–2d). Gena and postgena weakly lineolate. Mesoscutum weakly imbricate, polished posteriorly,
punctation fine, sparse between parapsidal lines (i=1–4d), moderately dense laterad of parapsidal
lines (i=1–2d), contiguous on anterolateral portions. Mesoscutellum similar to mesoscutum, submedial punctation
sparse (i=1–4d). Axilla punctate. Metanotum minutely reticulate. Preëpisternum rugulose. Hypoepimeral
area weakly imbricate-punctate (i≤d). Mesepisternum weakly imbricate, faintly polished, distinctly
punctate (i=1–2.5d). Metepisternum with dorsal half striate, ventral half imbricate. Metapostnotum incompletely
rugoso-striate, posterior margin weakly imbricate. Propodeum with dorsolateral slope rugulose, lateral
surface ruguloso-imbricate, posterior surface rugulose. Metasomal terga weakly coriarious, punctation on
basal halves moderately dense (i=1.5–3), impunctate on apical halves impunctate (except along premarginal
Structure. Head wide (length/width ratio = 0.93–0.94). Eyes weakly convergent below (UOD/LOD =
1.08–1.09). Clypeus 1/2 below suborbital tangent, apicolateral margins convergent. Antennal sockets close
(IAD/OAD < 0.5). Frontal line carinate, ending 2 OD below median ocellus. IOD subequal to OOD. Gena
wider than eye. Inner metatibial spur pectinate with 3–4 teeth. Metapostnotum posterior margin rounded.
Metapostnotum moderately elongate (MMR ratio = 1.29–1.46), posterior margin rounded onto posterior surface.
Propodeum with oblique carina strong, lateral carina strong, reaching dorsal margin.
MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 6.95–
7.50 mm; head length 1.78–1.90 mm; head width 1.75–1.85 mm; forewing length 4.82–5.55 mm
Colouration. Tarsi brownish yellow.
Pubescence. Face with very sparse tomentum. Lower paraocular area with moderately dense tomentum.
S2 apical portion with weak subappressed hairs. S3 apical half and S4 lateral portion with dense subappressed
plumose hairs (1–2 OD).
Surface sculpture. Mesepisternum distinctly punctate. Metanotum rugose. Propodeum with dorsolateral
slope strongly rugose, lateral and posterior surfaces rugulose.
Structure. Head moderately elongate (length/width ratio = 1.01–1.03). Eyes strongly convergent below
(UOD/LOD = 1.38–1.40). Clypeus 1/2–2/3 below suborbital tangent, apicolateral margins weakly convergent.
Antennal sockets distant (IAD/OAD > 1.2). Frontal line carinate, ending <2 OD below median ocellus. Pedicel
less than F1. F2 length 1.8–2.0X F1. F2–F10 moderately elongate (length/width ratio = 1.60–1.87). Metapostnotum
moderately elongate (MMR ratio = 1.21–1.38), posterior margin weakly angled onto posterior
Terminalia. S7 with median lobe columnar to weakly clavate, apex rounded (Fig. 152D). S8 with apicomedial
margin strong convex (Fig. 152D). Genitalia as shown in Fig. 152D–E. Gonobase with ventral arms
widely separated. Gonostylus small, dorsal setae elongate. Retrorse lobe elongate, weakly attenuated apically.
Range. Nova Scotia west to British Columbia, south to Georgia (Fig. 150).
Additional material examined. CANADA: BRITISH COLUMBIA: 1♀ North Okanagan Reg. Dist.,
Cherryville, Monashee P.P., Rum Crk., N50.5099 W118.2785, 1245 m, 20.vii.2008 (L.R. Best); [PCYU];
MANITOBA: 2♀♀ Duck Mt. P.P., Garland R., 1.vii.1962 (D. Barr); [ROM]; NOVA SCOTIA: 2♀♀ Kings
Co., Kentville, N45.0628 W064.4881, 29.v.2001 (C. Sheffield); 1♀ Kings Co., Weston, Brooklyn St.,
25.vi.2003 (Jansen, Sheffield & Rigby); ONTARIO: 1♀ Wentworth Co., 7.vi.2006, 10:00h–10:30h (V.
MacPhail); [PCYU]; USA: MAINE: 1♀ Aroostook Co., Allagash River Waterway, 18.viii.2006 (M.F. Veit);
MARYLAND: 1♀ Garrett Co., N39.2992 W79.42, 2004 (S.W. Droege); MASSACHUSETTS: 1♀ Middlesex
Co., Harvard: Oxbow NWR, 28.v.2006 (M.F. Veit); NEW HAMPSHIRE: 1♂ Carroll Co., Effingham, Rt 25 at
Ossipee Riv., 12.viii.2006 (M.F. Veit); NEW YORK: 2♀♀ Steuben Co., N46.3682 W077.3326, 26.vi.2004
(S.W. Droege); VERMONT: 2♂♂ Lamoille Co., 4.5 mi NE Hyde Park, 28.vii2006 (M.F. Veit); [PCYU];
WISCONSIN: 1♂ Door Co., N45.07475 W87.09224, 2.viii.2005 (C. Destree); [ARC].
Floral records. ASTERACEAE: Solidago, Taraxacum, BRASSICACEAE: Barbarea, CORNACEAE:
Cornus, FABACEAE: Lupinus polyphyllus, Trifolium, ONAGRACEAE: Epilobium, PLANTAGINACEAE:
Plantago, ROSEACEAE: Amelanchier, Aruncus, Fragaria, Malus, Prunus, Rosa, SALICACEAE: Salix.
Extracted from Jason Gibbs. 2011. Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini.) Zootaxa.
Lasioglossum (Dialictus) nigroviride (Graenicher)
Halictus nigro-viridis Graenicher, 1910: 233. ♀.
Holotype. ♀ USA, Wisconsin, Swiss, Burnett Co., 27.vii.1909, [Milwaukee: 32837].
Halictus (Chloralictus) richardsoni Cockerell, 1937: 113. ♀.
Holotype. ♀ Canada, Alberta, Wabamun, 60 miles E of Edmonton, 1.vii.1935 (E.H. Strickland); [CNC: 4169]. Examined
Evylaeus pineolensis Mitchell, 1960: 358. ♂ . [new synonymy]
Holotype. ♂ USA, North Carolina, Pineola, 3.viii.1937 (D.L. Wray); [NMNH: 100875]. Examined. .
Dialictus nigroviridis Knerer and Atwood, 1962b: 169 (Emend.)
Taxonomy. Cockerell, 1937: Halictus (Chloralictus) nigroviridis, p. 113 (diagnosis); Michener, 1951: Lasioglossum
(Chloralictus) nigro-viride, p. 1115, L. (C.) richardsoni, p. 1117 (catalogue); Mitchell, 1960: Dialictus nigro-viridis ♀♂,
p. 406 (redescription); Krombein, 1967: Lasioglossum (Dialictus) nigroviride, p. 464 (catalogue); Hurd, 1979: Dialictus
nigroviridis, p. 1968, D. richardsoni, p. 1971 (catalogue); Moure & Hurd, 1987: Dialictus nigroviridis, p. 115, D. richardsoni,
p. 127 (catalogue); Gibbs, 2010b: Lasioglossum (Dialictus) nigroviride ♀♂, p. 203 (redescription, key, synonymy).
Diagnosis. Female L. nigroviride can be recognised by the following diagnostic combination: size large (7.0–8.1
mm); head and mesosoma golden; gena wider than eye; mesoscutal punctures sparse between parapsidal lines (i=1–4d),
sometimes sparse laterad of parapsidal line (i=1–2d); mesepisternal punctures distinct, sparse (i=1–2.5d) (Fig. 24A); lateral
carina reaching or nearly reaching oblique carina (Fig. 2B); and metasomal terga black-brown, tomentum and apical
fringes. They are superficially similar to L. obscurum, which is smaller (4.9–5.9 mm) with weak propodeal carinae, and
sparse apical fringe hairs on metasomal terga.
Male L. nigroviride can be recognised by the following diagnostic combination: size large (7.0–7.5 mm); head and
mesosoma golden green; flagellomeres elongate (length/width ratio = 1.60–1.87); mesoscutum polished due to weak
microsculpture, punctures sparse between parapsidal lines (i=1–4d); mesepisternal punctures distinct; metasomal terga blackish brown; and S3 and apicolateral portions of S4 with very dense plumose hairs. Male L. obscurum are similar but have relatively sparse hairs on the metasomal sterna.
Range. Nova Scotia west to British Columbia, south to Georgia. USA: GA, MA, MD, ME, NC, NH, NY, PA, VT,
WA, WI, WV. CANADA: AB, BC, MB, NS, ON.
DNA Barcode. Available. Multiple sequences.