Identification Summary: Large; similar to L. rohweri; T1 hair fan always with a small opening at the top where the hairs are absent; T2 and T3 with a thin strip of appressed white hairs that run along the base, sometimes covered when segment is partially retracted into the preceding one, this strip often contrasts sharply with the very black segment integument; unlike L. rohweri the appressed rim of T2 with almost no pits; rims of tergites usually without any color, again in contrast to L. rohweri.
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 5-7 mm.; head and thorax olive green, abdomen more piceous, with greenish reflections; pubescence short, thin, entirely pale, abdominal terga 2 and 3 with rather conspicuous, basal fasciae of dense tomentum and 4 partially obscured by pale tomentum; length and breadth of head sub- equal; clypeus broadly convex, projecting about one-half below suborbital line; supraclypeal area nearly as long as broad and only very slightly shorter than clypeus; eyes convergent below; lateral ocelli slightly nearer eyes than to each other; cheeks subequal to eyes in width; face below ocelli dull, punctures deep, distinct, rather fine and densely crowded, becoming rather obscure and indefinite on vertex; cheeks rather dull, obscurely and minutely punctate above, becoming finely striate posteriorly, smooth and shining below; hypostomal carinae parallel, apical angle rather narrowly rounded; scutum and scutellum rather dull, finely tessellate, punctures rather fine but deep and distinct (much like rohweri, fig. 99) but usually more finely punctate, scutellum with a slightly impressed and closely punctate median line; pleura rather dull, obscurely subrugose anteriorly, becoming relatively smooth but finely roughened posteriorly and below; dorsal area of propodeum rather broad, with a single, nearly complete, median striae, obscurely and finely substriate on each side of this, but becoming coarsely striate laterally, lateral surfaces somewhat shining, very finely roughened and with scattered, obscure punctures; wings subhyaline, veins and stigma yellowish-testaceous; tegulae brownish-testaceous, becoming hyaline anteriorly; legs piceous, becoming only very slightly more brownish apically; abdominal terga smooth, somewhat shining, basal tergum practically impunctate, 2nd and 3rd with exceedingly minute, rather close punctures across basal half, apical half nearly impunctate, with basal, white, tomentose fasciae which are very narrow medially, broad and usually conspicuous laterally, tergum 4 largely obscured by whitish tomentum.
MALE�Length 6 mm.; head and thorax olive green, abdomen more piceous, margins of terga quite conspicuously yellowish-hyaline; pubescence short, thin, entirely white, quite dense on face, rather copious on cheeks and thorax; length and breadth of head subequal; clypeus convex, rather narrow and protuberant, projecting about two-thirds below suborbital line; supraclypeal area subequal in length to clypeus; eyes strongly convergent below; lateral ocelli subequally distant from eyes and each other; antennae somewhat nearer eyes than each other, basal segment of flagellum about as broad as long, slightly longer than pedicel, following segments about one and a half times as long as broad, pale testaceous beneath, becoming brownish above; cheeks subequal to eyes in width; face below ocelli somewhat shining between deep, distinct, rather coarse and very close punctures, these becoming somewhat more separate on vertex; cheeks rather dull, very minutely and closely punctate above, becoming finely and rather obscurely striate below, lower surface more shining; hypostomal carinae subparallel; lower half of face obscured by dense, white pubescence, punctures beneath deep, distinct and very close, supraclypeal area closely and finely punctate, and clypeus similarly punctate above, but punctures becoming somewhat more widely separated apically; scutum and scutellum rather dull and tessellate, deeply and distinctly punctate, punctures well separated medially on scutum, becoming almost crowded laterally, those on scutellum irregularly scattered, rather close in general; pleura dull rather finely rugose anteriorly, becoming somewhat smoother or subrugose posteriorly; dorsal area of propodeum rather coarsely and quite completely rugoso-striate medially, becoming somewhat more regularly striate laterally, lateral faces rather dull, very finely substriate or subrugose; wings hyaline, veins and stigma testaceous; tegulae yellowish-hyaline; legs piceous basally, tibiae more brownish and somewhat yellowish basally and apically, tarsi entirely yellow; abdominal terga somewhat shining, rather closely, evenly and fully, but very finely punctate, punctures disappearing toward apical margins, these only narrowly impressed and becoming distinctly but rather narrowly whitish-hyaline along rim, terga 3- 5 partially obscured by thin, pale tomentum; apical margin of sternum 5 slightly incurved; sternum 7 much as in repliyrus (fig. 101), but median process somewhat broader, with parallel sides and broadly rounded apex; gonostylus of armature as shown (fig. 102), retrorse lobe small, well covered with minute hairs.
DISTRIBUTION�Minnesota to Nova Scotia, south to Louisiana and Georgia; March to October.
FLOWER RECORDS�Antennaria, Apocynum, Aster, Barbarea, Berteroa, Ceanothus, Clematis, Crataegus, Fagopyrum, Hydrangea, Medicago, Melilotus, Potentilla, Prunus, Rudbeckia, Salix, Senecio, Solidago, Taraxacum and Trifolium.
This is a quite variable species, exhibiting in the female not only a considerable range in size (5-7 mm.), but also in the width of the cheeks, the sculpture of the mesopleura, the degree of development of the basal tomentose fasciae on the 2nd and 3rd abdominal terga, and in the color. The type in the British Museum has been seen and a specimen compared with it is at hand. The type of euryceps is in the collection of the California Citrus Experiment Station at Riverside, and a specimen compared with that type has been received from Timberlake. The differences between these two homotypes are minor, at most, and seem to this writer to be individual variations. A considerable amount of material of this species has been studied, and considerable effort has been expended in an attempt to find points of contrast which would suggest specific or subspecific differences, but without success. In the larger specimens the cheeks usually are somewhat broader than the eyes, but in smaller individuals they are of about the same width. The pleura are dull and subrugose anteriorly, but the posterior half may be finely roughened, smooth but dull, with obscure, scattered punctures, or somewhat shining, with distinct and rather close punctures. In most specimens abdominal terga 2 and 3 have distinct, basal, white, tomentose bands which are very narrow at the mid point, but are much broadened laterally. The degree to which they are evident depends in part on the flexing of the abdomen, being more conspicuous if that part is flexed downward toward the apex. In the darker specimens the head and thorax are olive green with the abdomen piceous, while in the lighter individuals the fore parts are more brassy- green and the abdomen with greenish reflections. No combination of these differences seems to have any relation to geographic distribution, hence it seems advisable not to recognize any of the variants as subspecies. Studies need to be made of nesting populations, to determine the range of variation and to verify or dispute the association of the sexes as given here.
Retrieved from: Gibbs, J. 2010. Revision of the metallic species of Lasioglossum (Dialictus)in Canada (Hymenoptera, Halictidae, Halictini). Zootaxa; 2591, 170-175
Halictus laevissimus Smith, 1853: 72. ♀.
Holotype. ♀ Canada, Manitoba, Arctic America. South of Lake Winnipeg, [BMNH: B.M. Type 17a 1002]. Examined.
Halictus levissimus Dalla Torre, 1896: 68 (Emend.)
Halictus smilacinae Robertson, 1897: 322. ♀.
Lectotype. ♀ USA, Illinois, Carlinville (C. Robertson); [INHS: 179618] by W.E. Laberge.
Halictus euryceps Ellis, 1914: 98. ♀.
Syntypes. ♀ USA, New Mexico, Beulah, end of August, (Cockerell); [CAS: 15605]; ♀ USA, New Mexico, Beulah,
27.vii., nesting (Cockerell), [MCZ: 13810]; ♀ USA, New Mexico, Beulah [ANSP]. Examined.
Halictus (Chloralictus) phaceliarum Cockerell, 1919: 299. ♀. [new synonymy]
Holotype. ♀ USA, Colorado, Peaceful Valley, Colorado, 26.viii.1918 (W.P. Cockerell); [NMNH: 40260]. Examined.
Halictus (Chloralictus) praepes Sandhouse, 1924: 30. ♂. [new synonymy]
Holotype. ♂ USA, Colorado, Peaceful Valley, 1919 (Cockerell); [NMNH: 26430]. Examined.
Halictus (Chloralictus) astutus Sandhouse, 1924: 31. ♂. [new synonymy]
Holotype. ♂ USA, New Mexico, Beulah, 18.viii. (W. Porter); [NMNH: 26431]. Examined.
Halictus (Chloralictus) abundus Sandhouse, 1924: 32. ♂. [new synonymy]
Holotype. ♂ USA, New Mexico, Beulah, end of viii (Cockerell); [NMNH: 26432]. Examined.
Halictus (Chloralictus) tranquillus Sandhouse, 1924: 32. ♂. [new synonymy]
Holotype. ♂ USA, New Mexico, Santa Fe, vii (Cockerell); [NMNH: 26433]. Examined.
Halictus (Chloralictus) jameseae Cockerell, 1933: 41. ♂. [new synonymy]
Holotype. ♂ USA, Colorado, Pingree Park, 15.viii.1932, (H. James); [CAS: 15610]. Examined.
Dialictus solidaginis Mitchell, 1960: 443. ♂. [new synonymy]
Holotype. ♂ USA, Michigan, Marquette Co., 20.vi.1955 (R.R. Dreisbach); [NCSU]. Examined.
Taxonomy. Robertson, 1902: Chloralictus smilacinae, p. 249 (key); Cockerell, 1905: Halictus laevissimus ♀,
p. 351 (tax. notes); Michener, 1951: Lasioglossum (Chloralictus) abundus, p,. 1111, L. (C.) astutus p. 1112, L.
(C.) jameseae, p. 1114, L. (C.) laevissimum, p. 1114, L. (C.) phaceliarum, p. 1116, L. (C.) praepes, p. 1116, L.
(C.) tranquillum, p. 1118 (catalogue); Mitchell, 1960: Dialictus laevissimus ♀(♂ misdet.), p. 401 (redescription);
Knerer & Atwood, 1962: Dialictus laevissimus ♂, p. 1228 (description); Krombein, 1967: Lasioglossum
(Dialictus) laevissimum, p. 464, L. (D.) solidaginis, p. 466 (catalogue); Hurd, 1979: Dialictus abundus, p.
1963, D. astutus, p. 1964, D. jameseae, p. 1967, D. phaceliarum, p. 1970, D. praepes, p. 1970, D. solidaginis,
p. 1971, D. tranquillus, p. 1972 (catalogue); Moure & Hurd, 1987: Dialictus abundus, p. 87, D. astutus, p. 91,
D. jameseae, p. 109, D. phaceliarum, p. 121, D. praepes, p. 124, D. solidaginis, p. 130, D. tranquillus, p. 135
(catalogue).
Diagnosis. Females of L. laevissimum can be recognised by the diagnostic combination of a large size
(5.1�7.1 mm), wide head (length/width 0.89�0.95), gena often wider than eye especially in larger individuals,
mesoscutal punctures sparse on central disc (i=1�3d), mesepisternum rugulose, metapostnotum incompletely
striate, T1 acarinarial fan small but complete or with narrow dorsal opening, blackish brown metasomal terga
with apical halves impunctate (except along premarginal line) and T3 usually with a sharply contrasted basal
band of white tomentum. They are similar to L. pacatum and L. marinense. Female L. pacatum have moderately
elongate head (length/width ratio = 0.96�1.00) and the gena narrower than the eye. Female L. marinense
have virtually no tomentum on the metasomal terga and the gena narrower than the eye.
Males of L. laevissimum can be recognised by their large size (5.4�6.7 mm), face with dense tomentum
limited to lower paraocular area, elongate flagellomeres (length/width ratio = 1.64�2.00), moderately polished
mesoscutum due to weak microsculpture, rugulose mesepisternum with obscure punctures on ventral portion,
and apical impressed areas of the metasomal terga impunctate. They are most similar to L. ephialtum which
have the mesoscutum dull due to microsculpture.
Redescription. FEMALE. Length 5.12�7.10 mm; head length 1.34�1.85 mm; head width 1.51�2.02 mm;
forewing length 4.15�5.19 mm.
Colouration. Head and mesosoma pale blue or green with golden reflections. Clypeus with apical half
blackish brown and basal half, and supraclypeal area with brassy reflections. Antenna dark brown, flagellum
with ventral surface reddish brown. Tegula reddish brown. Wing membrane subhyaline, venation and
pterostigma amber. Legs brown, tarsi reddish brown. Metasoma blackish brown, terga and sterna with apical
margins brown
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). Paraocular area with sparse subappressed
hairs. Gena with sparse tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior
surfaces (2�2.5 OD). Metasomal terga with sparse, fine setae. T1 acarinarial fan with small dorsal opening. T2
basolateral area with appressed tomentum. T3 typically with distinct basal band of white tomentum. T4�T5
with scattered tomentum partially obscuring surface.
Surface sculpture. Face imbricate, punctation fine. Clypeus with apical half polished, punctation moderately
sparse (i=1�3d). Supraclypeal area with punctation moderately sparse (i=1�4d). Lower paraocular and
antennocular areas with punctation moderately dense (i=1�1.5d). Upper paraocular area and frons punctatereticulate.
Ocellocular area punctate (i=1�1.5d). Gena and postgena lineolate. Mesoscutum imbricate, posterior
portion polished, punctation fine, moderately sparse between parapsidal lines (i=1�3d), dense laterad of
parapsidal lines (i>=d), contiguous on anterolateral portions. Mesoscutellum similar to mesoscutum, submedial
punctation sparse (i=1�4d). Axilla punctate. Metanotum ruguloso-imbricate. Pre�pisternum rugulose.
Hypoepimeral area weakly rugulose. Mesepisternum dorsal half weakly rugose, ventral half imbricate.
Metepisternum with dorsal third rugoso-striate and ventral portion imbricate. Metapostnotum incompletely
rugoso-striate, medial striation distinctly longer than submedial striations, posterior margin imbricate. Propodeum
with dorsolateral slope rugose, lateral and posterior surfaces imbricate. Metasomal terga polished
except apical impressed areas weakly coriarious, punctation on basal halves moderately sparse (i=1.5�2d),
apical half impunctate (except along premarginal line).
Structure. Head very wide (length/width ratio = 0.89�0.95). Eyes weakly convergent below (UOD/LOD
ratio = 1.08�1.17). Clypeus � below suborbital tangent, apicolateral margins strongly convergent. Antennal
sockets close (IAD/OAD < 0.5). Frontal line carinate, ending 2 OD below median ocellus. Gena wider than,
or equal to, eye. Inner metatibial spur pectinate with 3�5 teeth. Metapostnotum moderately elongate (MMR
ratio = 1.19�1.30), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina
moderately strong, lateral carina moderately strong, nearly reaching dorsal margin.
MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.43�
6.70 mm; head length 1.49�1.85 mm; head width 1.54�1.87 mm; forewing length 4.09�5.06 mm.
Colouration. Flagellum with ventral surface reddish orange to yellow-orange. Wing membrane subhyaline,
venation and pterostigma dark amber to brown. Tarsi reddish to yellow-orange.
Pubescence. Lower paraocular area with dense tomentum obscuring most of surface. Clypeus, and supraclypeal
area with scattered tomentum not obscuring surface. S2�S4 with dense posteriorly directed hairs
which are absent along the midline.
Surface sculpture. Mesepisternal punctation distinct on ventral portion. Metapostnotum coarsely rugose.
Propodeum with lateral and posterior surfaces coarsely rugose. Metasomal terga punctation coarse, apical
impressed area impunctate.
Structure. Head moderately wide (length/width ratio = 0.97�0.99). Eyes strongly convergent below
(UOD/LOD ratio = 1.45�1.54). Antennal sockets distant (IAD/OAD > 1.5). Frontal line carinate, ending 1.5
OD below median ocellus. Pedicel shorter than F1. F2 length 2.0X F1. F2�F10 elongate (length/width ratio =
1.64�2.00). Metapostnotum moderately elongate (MMR ratio = 1.21�1.30), posterior margin rounded or
weakly angled onto posterior surface.
Terminalia. S7 with median lobe clavate, apex rounded (Fig. 133F). S8 with apicomedial margin weakly
convex (Fig. 133F). Genitalia as in Fig. 133D�E. Gonobase with ventral arms narrowly separated. Gonostylus
small, dorsal setae elonagate. Retrorse lobe moderately elongate, attenuated apically.
Range. Nova Scotia west to British Columbia, south to New Mexico (Fig. 129).
Additional material examined. CANADA: ALBERTA: 3♂♂ 15 km S Three Hills, Hwy 21, N51.49484
W113.23214, 702 m, 2.ix.2007 (Gibbs & Sheffield); [PCYU]; 7♀♀6♂♂ Edmonton, 30.viii.1984 (Thormin,
Spanton & Nicholson); [PMAE]; BRITISH COLUMBIA: 2♀♀ Aldergrove, 50�100 m, 3.vii.1978 (N.L.H.
Krauss); [AMNH]; 1♀ Cowichan Lake Forestry Station, Ministry of Forests, Mesachie Lake, N48�49�07.9��
W124�08�05.1��, 11.v.2005 (E. Elle); 1♀ Cowichan Lake Forestry Station, Ministry of Forests, Mesachie
Lake, N48�49�07.9�� W124�08�05.1��, 13.vii.2005 (E. Elle); NEW BRUNSWICK: 1♀ Kent Co., St. Ignace,
15.viii.2005 (A.I. Gravel); 2♀♀ Kent Co., St. Ignace, N46.707 W071.054, 31.vii.2005 (M. Gravel); [PCYU];
NORTHWEST TERRITORIES: 4♂♂ Mackenzie Dist., Norman Wells, N65�15′15′′ W126�41′15′′, 22.viii�
1.ix.2005 (D. Currie & R. Popko); [ROM]; NOVA SCOTIA: 1♀ Kings Co., Avonport, N45.1198 W064.273,
28.ix.2002 (C. Sheffield); 1♀ Kings Co., Avonport, N45.1198 W064.273, 29.ix.2002 (C. Sheffield); 1♀ Kings
Co., Lakeville, N45.113 W065.5849, 8.vi.2003 (Sheffield, Rigby & Jansen); [PCYU]; ONTARIO: 1♀ Ottawa, 26.iv.1916 (F.W.L. Sladen); [CNC]; 1♀ York University, N43.772 W079.497, 24.v.2006 (J. Gibbs);
1♀ York University, N43.772 W079.497, 26.vi.2006 (J. Gibbs); PRINCE EDWARD ISLAND: 1♀ Queens
Co., 6.vii.2006 (V. MacPhail); 2♀♀ Queens Co., 7.vii.2006 (V. MacPhail); 1♀ Queens Co., 8.vii.2006 (V.
MacPhail); [PCYU]; SASKATCHEWAN: 1♀ Saskatoon, 28.vii.1977 (N.L.H. Krauss); [AMNH]; USA:
COLORADO: 2♀♀ Park Co., 13 km N Eleven Mile S.P., N38.99079 W105.42997, 2671 m, 30.vii.2007
(Gibbs & Sheffield); [PCYU]; MAINE: 6♀♀ Acadia, Gt. Pond, 18.vii.1978 (P.E. Hallett); [PHPC]; MARYLAND:
2♀♀ Garrett Co., N39.3097 W079.4577, (S.W. Droege); MICHIGAN: 1♀ Allegan Co., N42.5538
W086.0437, 28.viii.2003 (S.W. Droege); NEW MEXICO: 1♀ Otero Co., Cloudcroft, 8500ft, 31.vii.1972,
(G.C. Eickwort); [CUIC]; NORTH CAROLINA: 2♀♀ Swain Co., Great Smoky Mtn. N.P., Andrew�s Bald,
N35.5396 W083.4942, 6.viii.2006 (J. Gibbs); [GSNP]; OHIO: 1♀ near Cuyahoga Valley N.P., N41.24065
W081.54465, 16.viii.2006 (J. Gibbs); UTAH: 1♀ San Juan Co., La Sal Mtns., Warner Lk., 9400 ft.,
29.vi.1999; [PCYU].
Floral records. LINACEAE: Linum lewisii, ROSACEAE: Amelanchier, Cratategus, Fragaria, Potentilla,
Prunus, Rosa, Rubus, ASTERACEAE: Anaphalis, Antennaria, Aster, Hieracium, Rudbeckia, Senecio,
Solidago canadensis, S. velutina, Taraxacum, APOCYNACEAE: Apocynum, BRASSICACEAE: Barbarea,
Berteroa, RHAMNACEAE: Ceanothus, RANUNCULACEAE: Clematis, CORNACEAE: Cornus, THYMELAEACEAE:
Dirca palustris, ONAGRACEAE: Epilobium, POLYGONACEAE: Fagopyrum, GENTIANACEAE:
Frasera, APIACEAE: Heracleum maximum, HYRANGEACEAE: Hydrangea, FABACEAE:
Medicago, Melilotus, Trifolium, HYDROPHYLLACEAE: Phacelia, POLEMONIACEAE: Polemonium aff.
caeruleum, ANACARDIACEAE: Rhus, SALICACEAE: Salix, LILIACEAE: Maianthemum stellatum.
Biology. Brittain, 1933: (pollination as smilacinae); Evans & Lin, 1959: (predator, as euryceps); Knerer &
Atwood, 1962: (nest site, geography, floral records); Evans, 1964: (predator); Knerer & Atwood, 1967: (parasite);
Evans, 1970: (predators); Alcock, 1974: (predators); Delfinado & Baker, 1976: (mite association);
Batra, 1987: (ethology); Packer, 1992: (social organization); Packer & Owen, 1994: (relatedness, sex ratio).
Comments. Common. The male of L. laevissimum has been described under different names several
times. Mitchell (1960) incorrectly associated the sexes of this species but Knerer and Atwood (1962a) remedied
the situation. The extensive size variation and widespread abundance of this species are two factors
which have contributed to the numerous synonymies for this species.
Lasioglossum (Dialictus) leucocomum (Lovell), new combination
(Figure 134A�C)
Halictus pilosus
Extracted from Jason Gibbs. 2011. Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini.) Zootaxa.
Lasioglossum (Dialictus) laevissimum (Smith)
Halictus laevissimus Smith, 1853: 72. ♀.
Holotype. ♀ Canada, Manitoba, Arctic America. South of Lake Winnipeg, [BMNH: B.M. Type 17a 1002]. Examined.
Halictus levissimus Dalla Torre, 1896: 68 (Emend.)
Halictus euryceps Ellis, 1914: 98. ♀.
Holotype. ♀ USA, New Mexico, Beulah, end of August, (Cockerell); [CAS: 15605]. Examined.
Halictus (Chloralictus) phaceliarum Cockerell, 1919: 299. ♀.
Holotype. ♀ USA, Colorado, Peaceful Valley, Colorado, 26.viii.1918 (W.P. Cockerell); [NMNH: 40260]. Examined.
Halictus (Chloralictus) praepes Sandhouse, 1924: 30. ♂.
Holotype. ♂ USA, Colorado, Peaceful Valley, 1919 (Cockerell); [NMNH: 26430]. Examined.
Halictus (Chloralictus) astutus Sandhouse, 1924: 31. ♂.
Holotype. ♂ USA, New Mexico, Beulah, 18.viii. (W. Porter); [NMNH: 26431]. Examined.
Halictus (Chloralictus) abundus Sandhouse, 1924: 32. ♂.
Holotype. ♂ USA, New Mexico, Beulah, end of viii (Cockerell); [NMNH: 26432]. Examined.
Halictus (Chloralictus) tranquillum Sandhouse, 1924: 32. ♂.
Holotype. ♂ USA, New Mexico, Santa Fe, vii (Cockerell); [NMNH: 26433]. Examined.
Halictus (Chloralictus) jameseae Cockerell, 1933: 41. ♂.
Holotype. ♂ USA, Colorado, Pingree Park, 15.viii.1932, (M. James); [CAS: 15610]. Examined.
Dialictus orbitatus Mitchell, 1960: 440. ♂. [new synonymy]
Holotype. ♀ USA, North Carolina, Bluff Park, Scenic Hgwy., [Doughton Park, Blue Ridge Pkwy], 24.vi.1948 (T.B. Mitchell);
[NCSU]. Examined.
Dialictus solidaginis Mitchell, 1960: 443. ♂.
Holotype. ♂ USA, Michigan, Marquette Co., 20.vi.1955 (R.R. Dreisbach); [NCSU]. Examined.
Taxonomy. Cockerell, 1905: Halictus laevissimus ♀, p. 351 (tax. notes); Michener, 1951: Lasioglossum (Chloralictus)
abundus, p. 1111, L. (C.) astutus p. 1112, L. (C.) jameseae, p. 1114, L. (C.) laevissimum, p. 1114, L. (C.) phaceliarum, p.
1116, L. (C.) praepes, p. 1116, L. (C.) tranquillum, p. 1118 (catalogue); Mitchell, 1960: Dialictus laevissimus ♀(♂ misdet.),
p. 401 (redescription, key); Knerer & Atwood, 1962a: Dialictus laevissimus ♂, p. 1228 (description); Krombein,
1967: Lasioglossum (Dialictus) laevissimum, p. 464, L. (D.) orbitatum, p. 465, L. (D.) solidaginis, p. 466 (catalogue);
Hurd, 1979: Dialictus abundus, p. 1963, D. astutus, p. 1964, D. jameseae, p. 1967, D. orbitatus, p. 1969, D. phaceliarum,
p. 1970, D. praepes, p. 1970, D. solidaginis, p. 1971, D. tranquillus, p. 1972 (catalogue); Moure & Hurd, 1987: Dialictus
abundus, p. 87, D. astutus, p. 91, D. jameseae, p. 109, D. orbitatus, p. 118, D. phaceliarum, p. 121, D. praepes, p. 124, D.
solidaginis, p. 130, D. tranquillus, p. 135 (catalogue); Gibbs, 2010b: Lasioglossum (Dialictus) laevissimum ♀♂, p. 170
(redescription, key, synonymies).
Diagnosis. Female L. laevissimum can be recognised by the following diagnostic combination: size large (5.1�7.1
mm); head wide (length/width 0.89�0.95); gena often wider than eye, especially in larger individuals; mesoscutal punctures
sparse between parapsidal lines (i=1�3d); mesepisternum rugulose; metapostnotum incompletely carinulate; T1
acarinarial fan nearly complete, dorsal opening narrow; metasomal terga blackish brown, apical halves impunctate
(except along premarginal line), and T3 usually with sharply contrasted basal band of white tomentum. They are similar
to L. smilacinae, which lacks any dorsal opening in the T1 acarinarial fan, and have metasomal terga with distinctly punctate
apical impressed areas.
Male L. laevissimum can be recognised by the following diagnostic combination: size large (5.4�6.7 mm); face with
dense tomentum limited to lower paraocular area; flagellomeres elongate (length/width ratio = 1.64�2.00); mesoscutum
moderately polished due to weak microsculpture; mesepisternum rugulose, obscurely punctate ventrally; apical
impressed areas of metasomal terga impunctate; and S3 with dense hairs. They are most similar to L. abanci and L. ephialtum.
Male L. abanci have S3 with sparse hairs limited to apical portion. Male L. ephialtum, which has the mesoscutum
dull due to microsculpture.
Range. Nova Scotia west to British Columbia, south to New Mexico. USA: CO, IL, MD, ME, MI, MN, NC, ND,
NH, NM, NY, OH, PA, SD, UT, WI, WV. CANADA: AB, BC, MB, NB, NF, NS, NT, ON, PE, PQ, SK.
DNA Barcode. Available. Multiple sequences.
Comments. Common.
Lasioglossum laevissimum is known to form eusocial colonies (Packer 1992; Packer & Owen 1994).
Dialictus orbitatus is removed from synonymy with L. obscurum and placed into synonymy with L. laevissimum.
Halictus smilacinae, long considered to be a synonym of L. laevissimum, is resurrected (see below).
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