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Identification Summary: Rare; northern; defining feature is that the upper half of the mesepisturnum is quite as rough as L. cressonii but about half way down there is an ABRUPT transition to a smooth surface with scattered very clear pits; dark blue; fan restricted to just very tiny hair patches on the far sides. We would be interested in seeing additional specimens of this species.
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 6 mm.; head and thorax green, the cheeks and metapleura more or less bluish, abdominal terga piceous, becoming brownish apically; pubescence short, thin, entirely pale; head very slightly broader than long; clypeus convex, projecting slightly more than one-half below suborbital line; supraclypeal area nearly as long as broad, but considerably shorter than clypeus; eyes convergent below; lateral ocelli subequally distant from eyes and each other; cheeks subequal to eyes in width; face below ocelli rather dull, punctures quite deep and distinct, but very close and rather fine, becoming relatively sparse on vertex; cheeks above somewhat shining, punctures minute and obscure, smooth and shining below, hypostomal carinae parallel, apical angle abrupt; lower half of face rather dull and tessellate between shallow and rather coarse, well separated punctures, these becoming quite close toward clypeal margin, those on supraclypeal area fine and sparse; clypeal punctures well separated and fine along upper margin, becoming more coarse, deep and sparse apically, apical half blackened; scutum and scutellum somewhat shining, punctures fine and rather sparse on scutum medially, becoming somewhat closer but still well separated laterally (much as in inconspicuus, fig. 99), those on scutellum minute and close along a median line, sparse and irregular on each side; upper half of pleura coarsely reticulate, lower half quite smooth but dull, densely tessellate, and with scattered, well separated punctures; dorsal area of propodeum rather smooth medially, with a single, median, distinct striae, but becoming rather coarsely and regularly striate laterally, lateral surfaces rather smooth and shining; wings faintly brownish, veins and stigma testaceous; tegulae brownish, suffused with piceous; legs piceous, becoming somewhat brownish apically; abdominal terga shining, very minutely and obscurely punctate, basal tergum nearly impunctate, terga 2 and 3 with well separated, minute punctures across base, these becoming quite sparse apically, apical margins rather broadly but shallowly impressed, these areas somewhat brownish, becoming paler toward rims.
MALE—Length 5 mm.; head and thorax bluish-green, abdomen piceous; pubescence, short, thin, entirely pale; length and breadth of head subequal; clypeus convex, rather narrow and protuberant, projecting slightly more than one-half below suborbital line; eyes strongly convergent; lateral ocelli somewhat nearer eyes than each other; antennae much nearer eyes than each other, basal segment of flagellum about as broad as long, somewhat longer than pedicel, 2nd and following segments nearly twice as long, brownish-testaceous beneath, piceous above; mandibles and labrum dark; cheeks slightly narrower than eyes; face below ocelli dull, punctures rather coarse, deep and distinct but densely crowded, becoming minute and well separated on shining vertex; cheeks rather dull, finely striate in large part; hypostomal carinae parallel; lower half of face somewhat obscured by pale tomentum, punctures quite deep and distinct, but fine and slightly separated, those on supraclypeal area exceedingly minute and quite sparse, those on clypeus minute and well separated along upper margin, becoming slightly more coarse but more irregular apically; scutum and scutellum rather dull, finely tessellate, punctures fine but quite distinct, rather widely separated over central area of scutum, becoming rather close but still well separated between notaulices and tegulae, scutellum with a barely perceptible, median, impressed line along which the punctures are somewhat closer, quite sparse and minute on each side; pleura coarsely rugose over upper half, the lower half quite smooth but dull and tessellate, with scattered, shallow and very obscure punctures, the line of division between these two areas quite abrupt; dorsal area of propodeum very coarsely and completely striate, the median striae somewhat irregular, posterior margin of area quite definite, subcarinate, lateral faces rather dull, with a few irregular striations posteriorly and below; wings lightly infuscated, veins and stigma brownish-testaceous; tegulae brownish testaceous, becoming narrowly hyaline anteriorly; legs piceous basally, becoming dull brownish-testaceous on tarsi; abdominal terga shining, very minutely and rather closely punctate across basal half of discs, apical impressed area rather indefinite but entirely impunctate, concolorous with basal area except for an extremely narrow, pale, apical rim; apical margin of sternum 5 slightly incurved, 3 and 4 quite densely pubescent on each side of a median line, lobe of sternum 7 slightly narrowed apically, apex rounded; gonostylus of armature quite small, with an outer fringe of rather elongate hairs, otherwise with very short, fine pubescence (much as in laevissimu.s, fig. 102), retrorse lobe quite small, narrowed apically, very finely short pubescent.
TYPES—Holotype: Female, Clare Co., Mich., May 24, 1958 (Dreisbach) [Dreisbach). Allotype: Cheboygan Co., Mich., Aug. 18, 1957 (Dreisbach). Paratypes: MICHIGAN: 1 female, Arenac Co., June 20,
1948; 1 female, Clare Co., May 25, 1958; 1 female, Clinton Co., June 21, 1952; 1 female, Crawford Co., June 24, 1951; 1 female, Eaton Co., May 30, 1941; 1 female, Gladwin Co., June 10-16, 1951; 1 female, lonia Co., June 10, 1950; 1 female, losco Co., July 4, 1954; 1 female, Kalkaska Co., June 11, 1955; 1 female, Kant Co., June 13, 1948; 1 female, Lake Co., May 10, 1947; 1 female (abdomen missing), Midland Co., June 19, 1943; 2 females, Shiawassee Co., June 6, 1948 (all Dreisbach); 19, Washtenaw Co., Ann Arbor, June 22, 1949 (U.N. Lanham) ; and 1 female, Van Buren Co., June 11, 1949. NEW YORK: 1 female, Caroline—Harford, June 15, 1904;1 female, Ithaca, Aug. 8, 1947 (C. Robinson); 3 females, Ithaca, June 6 & 11, 1935, May 17, 1936 (H. K. Townes). MINNESOTA: 1 female, Houston Co., May 22, 1937; 1 female, Itaska Park, June 16, 1938 (both Mickel) ; 1 female, Itaska Park, July 20, 1937 (A. E. Pritchard). Paratypes are in collections of R. R. Dreisbach, the University of Michigan, Cornell University, the University of Minnesota, H. K. Townes, and the author.
Retrieved from: Gibbs, J. 2010. Revision of the metallic species of Lasioglossum (Dialictus)in Canada (Hymenoptera, Halictidae, Halictini). Zootaxa; 2591, 110-114
Dialictus dreisbachi Mitchell, 1960: 391. ♀ ♂.
Holotype. ♀ USA, Michigan, Clare Co., 24.v. 1958 (R. & K. Dreisbach); [NCSU]. Examined.
Taxonomy. Lasioglossum (Dialictus) dreisbachi Krombein, 1967: 463 (catalogue); Hurd, 1979: Dialictus
dreisbachi, p. 1966 (catalogue); Moure & Hurd, 1987: Dialictus dreisbachi, p. 99 (catalogue).
Diagnosis. Both sexes of L. dreisbachi are recognisable by the sharp delineation between the coarsely
rugose dorsal mesepisternum and the densely tessellate-punctate ventral mesepisternum (Fig. 97D). Females
share characters typical of the L. viridatum species-group such as clypeus apicolateral margin convergent,
mesoscutal punctation moderately sparse medially, T1 acarinarial fan incomplete dorsally, T2–T5 with sparse
tomentum and T2 apical half virtually impunctate (except along premarginal line).
Redescription. FEMALE. Length 5.06–5.43 mm; head length 1.49–1.52 mm; head width 1.54–1.58 mm;
forewing length 4.27–4.39 mm.
Colouration. Head and mesosoma blue or greenish blue. Clypeus distal half blackish brown. Supraclypeal
area greenish blue, sometimes with brassy reflections. Antenna blackish brown, flagellum with ventral surface
reddish brown to orange. Tegula dark reddish brown. Wing membrane subhyaline, venation and pterostigma
amber. Legs brown, medio- and distitarsi reddish brown. Metasoma blackish brown, terga and sterna with apical
margins reddish.
Pubescence. Dull white. Moderately 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 without 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 of appressed hairs with
wide dorsal opening. T2–T3 basolaterally and T4–T5 entirely with sparse, scattered tomentum. T2 apicolateral
and T3–T4 apical margins with very sparse bands.
Surface sculpture. Face imbricate, punctation fine, shallow. Clypeus with apical half polished, punctation
moderately sparse (i=1–3d). Supraclypeal area with punctation moderately sparse (i=1–2.5d). Lower paraocular
area punctation dense (i≤d). Antennocular area punctation moderately dense (i=1–1.5d). Upper paraocular
area and frons punctate-reticulate. Ocellocular area obscurely punctate (i=d). Gena lineolate. Postgena imbricate.
Mesoscutum tessellate-imbricate, with a polished longitudinal area halfway between midline and
parapsidal line, punctation fine, moderately sparse between parapsidal lines (i=1–2d), dense laterad of
parapsidal line (i≤d), contiguous on anterolateral portion. Mesoscutellum similar to mesoscutum, punctation
sparse (i=2–5d). Axilla minutely punctate. Metanotum imbricate. Preëpisternum rugose. Hypoepimeral area
rugulose. Mesepisternum dorsal half coarsely rugose, ventral half densely tessellate-imbricate with moderately
strong punctation (i=1–1.5d), dorsal and ventral halves of mesepisternum sharply delineated by change
in sculpture. Metepisternum with dorsal half strongly striate, ventral half ruguloso-imbricate. Metapostnotum
incompletely striate, interstices wide, posterior margin imbricate. Propodeum with dorsolateral slope rugose,
lateral surface imbricate, posterior surface tessellate. Metasomal terga weakly coriarious, punctation on basal
halves moderately dense (i=1.5d), extremely sparse on apical halves (i=3–6d).
Structure. Head wide (length/width ratio = 0.96–0.97). Eyes convergent below (UOD /LOD ratio = 1.18–
1.22). Clypeus 2/3 below suborbital line, anterolateral margins convergent. Antennal sockets close (IAD/
OAD < 0.5). Frontal line carinate, ending 2 OD below median ocellus. Gnea narrower than eye. Inner metatibial
spur pectinate with 3–4 teeth. Metapostnotum moderately elongate (MMR ratio = 1.20–1.32), posterior
margin weakly angled onto posterior surface. Propodeum with oblique carina virtually absent, lateral carina
moderately strong, reaching 2/3 of the distance to dorsal margin.
MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.76–
5.12 mm; head length 1.49–1.51 mm; head width 1.49–1.51 mm; forewing length 4.09–4.21 mm.
Colouration. Flagellum with ventral surface orange-yellow. Medio- and distitarsi reddish brown.
Pubescence. Lower face with sparse tomentum, partially obscuring surface except lower paraocular area
with dense tomentum obscuring surface. S3–S4 apicolateral portions with posteromedially directed hair tufts.
Surface sculpture. Metepisternum with dorsal half strongly rugose. Metapostnotum coarsely rugoso-striate.
Propodeum dorsolateral slope, lateral and posterior surfaces strongly rugose. Metasomal terga punctation
on basal halves close (i=2d), apical half impunctate (except along premarginal line).
Structure. Head moderately wide to round (length/width ratio = 0.98–1.00). Eyes strongly convergent
below (UOD /LOD ratio = 1.44–1.48). Antennal sockets distant (IAD/OAD > 1.4. Pedicel shorter than F1. F2
length 2X F1. F2–F10 (length/width ratio = 1.86–2.00). Metapostnotum moderately elongate (MMR ratio =
1.23–1.32), posterior margin sharply angled onto posterior surface.
Terminalia. S7 median lobe wide, columnar, apex rounded (Fig. 98G). S8 apical margin weakly convex
(Fig. 98G). Genitalia as in Fig. E–F, H. Gonobase with ventral arms narrowly separated. Gonostylus small,
dorsal setae elongate. Retrorse lobes elongate, attenuated apically (Fig. 98H).
Range. Ontario, west to Alberta, Wisconsin and southeast to Maryland (Fig. 99).
Additional material examined. CANADA: ALBERTA: 1♂ Edmonton, 22.viii.1984 (Thormin, Spanton,
Nicholson); [PMAE]; ONTARIO: 1♀ Algonquin P.P., by Crossbar Lake, 17T 0711719E 5022831N, 12–
27.v.2007 (E. Proctor); 1♀ Brock, 9.ix.2003 [PCYU]; 1♀ Iona, 25.v.1962 (G. Knerer); [ROM]; 1♀ Toronto,
16.vii.1991 [CNC]; 3♀♀ Wentworth Co., 7.vi.2006 (V. MacPhail); [PCYU]; USA: MICHIGAN: 1♂ allotype,
Cheboygen Co., 18.viii.1957 (R.R. Dreisbach); [NCSU]; WISCONSIN: 1♀ Brown Co., 3489 Yorkshire Dr.,
N44.54415 W087.90710, 25.v.2005 (A. Wolf); [PCYU].
Floral records. SALICACEAE: Salix.
Comments. Rare. This species belongs to the L. viridatum species-group.
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