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Identification Summary: Moderately sized; thorax midnight blue; abdomen with no appressed hairs, nearly black, and no yellow or light colored rims; T1 hair fan exists only as weak small patches at the far sides; T2 with few to no pits near the rim; lots of confusion in the past with other 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 5.5—6.0 mm.; head and thorax bluish-green, abdomen piceous, with metallic reflections; pubescence short, thin, entirely whitish; length and breadth of head subequal; clypeus convex, projecting nearly two-thirds below suborbital line; supraclypeal area nearly as long as broad and only very slightly shorter than clypeus; eyes convergent below; lateral ocelli somewhat nearer eyes than to each other; cheeks subequal to eyes in width; face below ocelli rather dull, punctures deep, distinct and quite close, rather fine, becoming minute and obscure on the shining vertex; cheeks rather dull, minutely and closely punctate, becoming more striate posteriorly and toward lower surface which is more shining; hypostomal carinae subparallel, apical angle rather narrowly rounded; lower half of face rather dull and tessellate, punctures rather fine and shallow, quite sparse, those on supraclypeal area very sparse, surface somewhat shining, clypeus rather finely and closely punctate along upper margin, punctures becoming somewhat more deep, distinct and more widely separated toward apical margin, apical half blackened; scutum and scutellum rather dull, punctures rather fine, distribution much as in rohweri, (fig. 99), scutellum somewhat more finely and closely punctate in midline than on either side; pleura dull, rather coarsely rugose anteriorly, becoming somewhat smoother but finely roughened posteriorly; dorsal area of propodeum completely but rather irregularly rugoso-striate medially, becoming more distinctly striate laterally, lateral faces somewhat shining, finely roughened; wings subhyaline, veins and stigma brownish-testaceous; tegulae brownish testaceous, becoming hyaline anteriorly; legs piceous basally, becoming somewhat reddened apically; abdominal terga smooth, more or less shining, basal tergum impunctate, terga 2 and 3 closely but very minutely and obscurely punctate across basal half, becoming impunctate apically, apical impressed area shallow and not very broad, concolorous with remainder of discs, apical terga without pale tomentum, the surface entirely exposed.
MALE—Length 5 mm.; head and thorax bluish-green, abdomen blackish, with rather faint metallic reflections; pubescence short, thin, entirely pale, quite dense on face and somewhat more copious on cheeks and thorax; length and breadth of head subequal; clypeus rather narrow, convex and quite protuberant, projecting nearly two-thirds below suborbital line; supraclypeal area slightly shorter than clypeus; eyes strongly convergent below; lateral ocelli subequally distant from eyes and each other; antennae much nearer eyes than to each other, basal segment of flagellum about as broad as long, slightly longer than pedicel, 2nd and following segments much longer, but not nearly twice as long as broad, pale brownish-testaceous below, becoming brownish-ferruginous above; cheeks somewhat narrower than eyes; face below ocelli dull, punctures fine, deep, distinct and quite close, becoming obscure and more sparse on vertex; cheeks rather dull, minutely and obscurely punctate above, becoming more striate posteriorly and below; hypostomal carinae parallel; lower half of face obscured by dense tomentum, but punctures fine, well separated, quite deep and distinct; scutum and scutellum rather dull and tessellate, punctures fine but quite distinct, rather widely separated in center of scutum, becoming quite close laterally, irregularly scattered and variable on scutellum, which is very slightly impressed medially; pleura dull, rugose anteriorly, becoming somewhat smoother or subrugose posteriorly; dorsal area of propodeum quite coarsely and irregularly, but completely rugoso-striate medially, becoming somewhat more regularly but closely striate laterally, lateral surfaces rather dull, irregularly and very finely rugoso-striate; wings hyaline, veins and stigma brownish-testaceous; tegulae more reddish-testaceous, becoming hyaline anteriorly; legs piceous basally, tibiae more brownish, with yellowish base and apex, tarsi entirely yellow; abdominal terga shining, punctures exceedingly minute and indistinct, basal tergum practically impunctate, terga 2 and 3 with only a few obscure punctures across basal half, apical impressed area rather shallow, nearly concolorous with remainder of discs, apical terga not obscured by pale tomentum; apical margin of sternum 5 slightly and very broadly incurved, 3 and 4 rather densely pubescent on each side of median line; median lobe of sternum 7 much like that in vierecki (fig. 101); retrorse lobe of genital armature attenuated apically, gonostylus resembling that in nigro-viridis (fig. 102), but somewhat more elongate.
DISTRIBUTION—Minnesota to Nova Scotia, south to Louisiana and Georgia; March to October.
FLOWER RECORDS—Aquilegia, Aruncus, Asclepias, Brassica, Gastalia, Eupatorium, Gerardia, Melilotus, Rudbeckia, Solidago, Taraxacum and Zizia.
Retrieved from: Gibbs, J. 2010. Revision of the metallic species of Lasioglossum (Dialictus)in Canada (Hymenoptera, Halictidae, Halictini). Zootaxa; 2591, 211-215
Halictus oblongus Lovell, 1905a: 40. ♀ ♂.
Type locality. ?Maine, 24.viii? [depository unknown]
Taxonomy. Lovell, 1905a: Halictus versans ♂, p. 39 (misdet.); Lovell, 1908: Halictus (Chloralictus)
oblongus ♂, p. 38 (description); Michener, 1951: Lasioglossum (Chloralictus) oblongum, p. 1115 (catalogue);
Mitchell, 1960: Dialictus oblongus ♀♂, p. 409 (redescription); Krombein, 1967: Lasioglossum (Dialictus)
oblongum, p. 465 (catalogue); Hurd, 1979: Dialictus oblongus, p. 1969 (catalogue); Moure & Hurd, 1987:
Dialictus oblongus, p. 116 (catalogue).
Diagnosis. Females of L. oblongum can be recognised by the diagnostic combination of a bluish green
head and mesosoma, round head (length/width ratio = 0.94–0.95), densely punctate supraclypeal area (i≤d),
imbricate mesoscutum with moderately sparse punctures on central disc (i=1–2d), weakly rugose mesepisternum,
metapostnotum very coarsely striate (Fig. 23A), T1 acarinarial fan with wide dorsal opening, and metasomal
terga polished with virtually no appressed tomentum (Fig. 156D). They are similar to L. marinense
which have the metapostnotum rugoso-striate.
Males of L. oblongum are similar to females but may be further distinguished by the moderately elongate
head (length/width ratio = 0.98–1.01), moderately elongate flagellomeres (length/width ratio = 1.54–1.58),
metapostnotum with coarse longitudinal rugae that reach the posterior margin and are separated by wide and
distinctly shining areas (Figs. 57A, 157D), and moderately dense plumose hairs on the apicolateral portions of
S3–S5.
Redescription. FEMALE. Length 4.91–6.61 mm; head length 1.46–1.63 mm; head width 1.54–1.73 mm;
forewing length 3.90–4.39 mm.
Colouration. Head and mesosoma bluish green to deep blue. Clypeus with apical half blackish brown and
basal half, and supraclypeal area greenish. Antenna dark brown, flagellum with ventral surface reddish brown
to brownish yellow. Tegula translucent reddish brown. Wing membrane subhyaline, venation and pterostigma dark amber. Legs dark brown, medio- and distitarsi reddish. Metasoma blackish brown, terga and sterna with
apical margins reddish to brownish yellow.
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). Lower paraocular area and gena without
subappressed tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces
(2–2.5 OD). Metasomal terga with sparse, fine setae, virtually no appressed tomentum, at most a few
obscure appressed hairs basolaterally. T1 acarinarial fan incomplete, dorsal opening wider than lateral
patches.
Surface sculpture. Face imbricate, punctation fine, shallow. Clypeus polished, punctation moderately
sparse (i=1–2d). Supraclypeal area with punctation dense (i≤d). 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 weakly lineolate. Postgena weakly imbricate. Mesoscutum
imbricate-tessellate, punctation moderately sparse between parapsidal lines (i=1–2), dense laterad of
parapsidal lines (i≤d), contiguous on anterolateral portions. Mesoscutellum similar to mesoscutum, submedial
punctation sparse (i=1–4d). Axilla punctate. Metanotum rugulose. Preëpisternum rugose. Hypoepimeral area
rugose. Mesepisternum dorsal portion weakly rugose and ventral portion rugulose. Metepisternum with dorsal
half rugoso-striate, ventral half imbricate. Metapostnotum strongly striate. Propodeum with dorsolateral slope
rugose, lateral surface rugulose, posterior surface imbricate. Metasomal terga polished except anterior and
posterior margins weakly coriarious, punctation on basal halves moderately sparse (i=1–2d), sparse on apical
halves (i=2–5d).
Structure. Head wide (length/width ratio = 0.94–0.95). Eyes convergent below (UOD/LOD ratio = 1.21–
1.26). Clypeus 1/3–1/2 below suborbital tangent, apicolateral margins. Antennal sockets close (IAD/OAD <
0.5). Frontal line carinate, ending 2.5 OD below median ocellus. Gena narrower than eye. Inner metatibial
spur pectinate with 3–5 teeth. Metapostnotum moderately elongate (MMR ratio = 1.17–1.27), posterior margin
weakly angled onto posterior surface. Propodeum with oblique carina weak, lateral carina moderately
strong, almost reaching dorsal surface.
MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.51–
5.49 mm; head length 1.39–1.50 mm; head width 1.42–1.49 mm; forewing length 3.84–3.97 mm
Colouration. Flagellum with ventral surface brown. Tegula reddish brown. Wing membrane dusky, venation
and pterostigma reddish brown. Tarsi reddish brown. Metasomal terga blackish.
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Pubescence. Face below antennal sockets with scattered appressed tomentum, partially obscuring surface.
Lower paraocular area with moderately dense tomentum obscuring surface. S3–S5 apicolateral portions with
moderately dense plumose hairs.
Surface sculpture. Metanotum rugose. Metapostnotum very strongly rugoso-striate. Metapostnotum
coarsely rugoso-striate, interstitial areas wide and shining. Propodeum with dorsolateral slope and lateral and
posterior surfaces rugose. Metasomal terga impunctate on posterior half (except along premarginal line).
Structure. Head round (length/width ratio = 0.98–1.01). Eyes strongly convergent below (UOD/LOD
ratio = 1.50–1.63). Clypeus 1/2 below suborbital tangent, apicolateral margins convergent. Antennal sockets
distant (IAD/OAD > 1.3). Frontal line carinate, ending 2 OD below median ocellus. Pedicel subequal to F1.
F2 length 1.9X F1. F2–F10 moderately elongate (length/width ratio = 1.54–1.58). Metapostnotum moderately
elongate (MMR ratio = 1.23–1.32), posterior margin sharply angled onto posterior surface.
Terminalia. S7 with median lobe narrowly clavate, sides subparallel, apex rounded. S8 with apicomedial
margin weakly convex. Genitalia as in Fig. 157E–F. Gonobase with ventral arms narrowly separated. Gonostylus
moderately large, dorsal setae elongate. Retrorse lobe elongate, weakly attenuated, recurved apically.
Range. Quebec, Ontario, south to Virginia, east to Massachusetts (Fig. 155).
Additional material examined. CANADA: ONTARIO: 1♀ Claireville, Woodbridge, 1.x.1977 (P.E. Hallet);
[PHPC]; 1♀ Lambton Co., N43°15.317´ W081°49.867´, 20.vi.2008 (A. Taylor); NOVA SCOTIA: 2♂♂
Kings Co., East Torbrook, N44.9266 W064.9301, 4.x.2001 (C. Sheffield); 1♀ Kings Co., Lockhartville,
N45.0850 W064.2337, 13.vi.2002 (C. Sheffield); [PCYU]; QUEBEC: 1♀ Gatineau Pk., Mountain Rd.,
12.vii.1965 (P.S. Corbet); [PMAE]; USA: DISTRICT OF COLUMBIA: 1♀ Washington, N38.9113
W076.9519, 6–7.vii.2004 (C. Osborn); INDIANA: 1♂ Porter Co., Indiana Dunes N.L., Howe’s Prairie,
N41°39´09´´ W087°04´15´´, 31.viii.2004 (R. Grundel); MARYLAND: 3♀♀ Montgomery Co., N38.97
W077.1565, 24.vi.2006 (S.W. Droege); 1♀ Pr. George’s Co., N39.0478 W076.7952, 31.vii.2002 (H.W. Ikerd);
MASSACHUSETTS: 1♀ Middlesex Co., Pepperell, Nissitisit Riv., 5.viii.2006 (M.F. Veit); 1♂ Worcester Co.,
Winchendon, Lk Denison Rec. Area, 21.vii.2006 (M.F. Veit); VIRGINIA: 3♀♀ Assateague I., N37.9144
W075.3379, 30.vi–1.vii.2006 (S.W. Droege); 1♀ Assateague I., N37.9804 W075.2926, 30.vi–1.vii.2006 (S.W. Droege); 1♀ Assateague I., N37.8904 W075.3402, 1–2.vii.2006 (S.W. Droege); WISCONSIN: 1♂ Iowa
Co., Avoca Prairie, N43.19501 W090.28733, 23.vii.2006 (A. Wolf); [PCYU].
Floral records. Due to the resurrection of L. planatum (below), the list of floral records taken from the
literature are likely to apply in part to both. Records marked with an asterisk have been verified for L.
oblongum. APIACEAE: Zizia, ASCLEPIADACEAE: Asclepias, ASTERACEAE: Eupatoriadelphus maculatus*,
Eupatorium, Rudbeckia, Solidago*, Taraxacum, BRASSICACEAE: Brassica, FABACEAE: Melilotus,
HYDROPHYLLACEAE: Hydrophyllum, LILIACEAE: “Smilacina” , LYTHRACEAE: Lythrum*,
NYMPHAEACEAE: Castalia, PONTEDERIACEAE: Pontederia*, RANUNCULACEAE: Aquilegia, Enemion
biternatum, ROSACEAE: Aruncus, Prunus, SCROPHULARIACEAE: Penstemon, UNCERTAIN
PLACEMENT: “Gerardia”.
Biology. Evans & Lin, 1959: (predator); Sakagami & Michener, 1962, pp. 14: (nesting substrate).
Comments. Uncommon. The location of the type specimen is unknown. The type depository is listed as
“Washington” in Moure and Hurd (1987) but was not found among the NMNH types, nor is it listed among
their type specimens. Lovell may not have designated a holotype as several of his other species have lectotypes
designated by later authors. Multiple species could potentially match Lovell’s (1905) original description
of Halictus oblongus. When Lovell (1908) synonymized H. oblongus with H. planatus he wrote: “Only a
single specimen of H. oblongus ♀ has been taken… it differs from H. planatus in some minor characters…the
bee described as H. planatus are common”. The form I have chosen seems to correspond with that of Mitchell
(1960) and differs from L. planatum (see below).
Extracted from Jason Gibbs. 2011. Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini.) Zootaxa.
Lasioglossum (Dialictus) oblongum (Lovell)
Halictus oblongus Lovell, 1905a: 40. ♀ ♂.
Syntypes. ♀♂ USA, Maine, Waldoboro, 24.viii, on Eupatorium perfoliatum [depository unknown].
Taxonomy. Lovell, 1905a: Halictus versans ♂, p. 39 (misdet.); Lovell, 1908: Halictus (Chloralictus) oblongus ♂, p. 38
(description); Michener, 1951: Lasioglossum (Chloralictus) oblongum, p. 1115 (catalogue); Mitchell, 1960: Dialictus
oblongus ♀♂, p. 409 (redescription, key); Krombein, 1967: Lasioglossum (Dialictus) oblongum, p. 465 (catalogue);
Hurd, 1979: Dialictus oblongus, p. 1969 (catalogue); Moure & Hurd, 1987: Dialictus oblongus, p. 116 (catalogue);
Gibbs, 2010b: Lasioglossum (Dialictus) oblongum ♀♂, p. 211 (redescription, key).
Diagnosis. Female L. oblongum can be recognised by the following diagnostic combination: head wide (length/
width ratio = 0.94–0.95); supraclypeal area densely punctate (i≤d); mesoscutum imbricate, punctures moderately sparse
between parapsidal lines (i=1–2d); mesepisternum weakly rugose; metapostnotum coarsely carinate with shining interstitial
areas; T1 acarinarial fan with wide dorsal opening; and metasomal terga polished, appressed tomentum virtually
absent.
Male L. oblongum are similar to females but may be further distinguished by the head relatively elongate (length/
width ratio = 0.98–1.01), flagellomeres moderately elongate (length/width ratio = 1.54–1.58), and S3 –S5 apicolateral
portions with moderately dense, plumose hairs.
Range. Quebec, Ontario, south to Virginia, east to Massachusetts. USA: DC, DE, IN, MA, MD, NJ, NY, VA, WI.
CANADA: ON, PQ.
DNA Barcode. Available. Multiple sequences.
Comments. Uncommon.
Lasioglossum oblongum has been reported to nest in rotten wood (Sakagami & Michener 1962). Individuals of L.
oblongum, in the sense used here, have indeed been collected from under the bark of fallen logs.
The name L. oblongum has been applied in a sense believed to be consistent with standard usage in the last 50 years
(see Mitchell 1960; Gibbs 2010b). Until the type series is located, it remains unclear if the species referred to here as L.
oblongum is the same as the one described by Lovell (1905a).
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