Identification Summary: Large; glossy; uniformly blue usually with major metallic sheen; abdomen usually also metallic blue but frequently with only a hint of metallic blue; no appressed hair on abdomen.
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.; entire body deep blue; pubescence very short, thin, entirely pale; head considerably broader than long; clypeus rather broadly convex, projecting about one-third below suborbital line; supraclypeal area quite broad, very much shorter than clypeus, rather strongly convex; eyes convergent below; lateral ocelli slightly nearer eyes than to each other; cheeks very slightly broader than eyes; face below ocelli somewhat shining between the deep, distinct, close and rather coarse punctures, these becoming finer and more sparse on the vertex laterally which is shining, cheeks shining above, microscopically punctate, punctures well separated but not sparse, becoming finely striate below, hypostomal carinae subparallel, being rather broadly rounded apically; lower half of face somewhat shining, punctures more widely separated, but hardly sparse, those on supraclypeal area well separated, those on clypeus quite sparse, not markedly coarser; scutum and scutellum shining, punctures deep and distinct, but variable in size, much as in unicus (fig. 99) but somewhat closer between notaulices and tegulae; pleura somewhat shining, rugose anteriorly, with rather coarse and close punctures medially, but these disappearing toward posterior margin; dorsal area of propodeum regularly and rather coarsely striate laterally, becoming more irregular and incomplete medially, lateral surfaces rather dull, subrugose; wings subhyaline, veins and stigma brownish-testaceous; tegulae reddish-hyaline; legs brownish; abdominal terga shining, very finely, but rather distinctly punctate, punctures irregularly and rather widely scattered on basal tergum, rather close across base of terga 2 and 3, sparse apically on these terga and rather sparse on 4, these entirely exposed, without pale tomentum.
MALE—Length 7 mm.; entire body bluish- green, with brighter green reflections; pubescence short, thin, entirely pale, somewhat more dense on cheeks and face; head very slightly broader than long; clypeus convex, rather narrow, projecting nearly one-half below suborbital line; eyes strongly convergent below; lateral ocelli somewhat nearer eyes than to each other; space between antennae nearly twice that separating each antenna from adjacent eye, basal segment of flagellum short, only slightly exceeding pedicel, about as broad as long, the following segments fully twice as broad as long, testaceous beneath, somewhat darker brownish above; mandibles reddened; cheeks much narrower than eyes; face below ocelli rather dull, very finely and closely punctate, punctures becoming more sparse and obscure on the shining vertex, cheeks above shining, microscopically and obscurely punctate, becoming very finely striate below, hypostomal carinae subparallel; lower half of face shining, very finely punctate, punctures well separated but not sparse, supraclypeal area and clypeus with rather distinct and fine punctures, these well separated, becoming somewhat more coarse toward apical margin of clypeus; scutum and scutellum shining, punctures very fine and irregular, quite sparse medially, becoming only slightly closer laterally, scutellum with a faint, median impression; pleura shining, distinctly and rather closely and coarsely punctate above, punctures becoming more fine and sparse below and posteriorly; dorsal area of propodeum regularly striate laterally, becoming irregularly rugoso-striate medially, lateral areas somewhat shining, finely roughened; wings subhyaline, veins and stigma brownish testaceous; tegulae reddish-hyaline, becoming more yellowish anteriorly; legs brownish basally, tarsi entirely yellow; abdominal terga shining, punctures very minute and rather obscure, especially on basal tergum, those on 2nd and following terga rather close but distinctly separated, becoming sparse apically toward sides, apical margins rather narrowly and obscurely impressed, this area more or less reddish-hyaline; apical margin of sternum 5 nearly straight, length of median lobe of sternum 7 about twice the breadth, rounded apically; gonostylus of armature as shown (fig. 102), retrorse lobe expansive, slightly broadened apically, finely short pubescent.
DISTRIBUTION—Minnesota to Massachusetts, south to Georgia; April to October.
FLOWER RECORDS—Barbarea, Claytonia, Daucus, Melilotus, Malus and Taraxacum. Robertson (1929) records this species on Amelanchier, Arabis, Cryptotaenia, Isopyrum, Osmorrhiza, Ribes and Zanthoxylum.
Retrieved from: Gibbs, J. 2010. Revision of the metallic species of Lasioglossum (Dialictus)in Canada (Hymenoptera, Halictidae, Halictini). Zootaxa; 2591, 97-101
Halictus coeruleus Robertson, 1893: 146. ♀ ♂.
Lectotype. ♀ USA, Illinois, Carlinville (C. Robertson); [INHS: 179,608] by W.E. LaBerge. Examined.
Taxonomy. Robertson, 1902: Chloralictus caeruleus, p. 248 (key); Viereck, 1916: Halictus (Chloralictus)
caeruleus, p. 706; Michener, 1951: Lasioglossum (Chloralictus) coeruleum, p. 1113. (catalogue); Mitchell,
1960: Dialictus coeruleus ♀♂, p. 387 (redescription); Krombein, 1967: Lasioglossum (Dialictus) coeruleum,
p. 463 (catalogue); Hurd, 1979: Dialictus coeruleus, p. 1965 (catalogue); Moure & Hurd, 1987: Dialictus
coeruleus, p. 95 (catalogue); Pesenko et al., 2006: Evylaeus coeruleus, p. 6 (review).
Diagnosis. Both sexes of L. coeruleum are easily recognisable by their large size (5.3–7.1 mm) and deep
metallic blue colouration (sometimes with green reflections) of the head, mesosoma and metasoma. Females
have the subapical tooth of the mandible larger than in other species, nearly equal in size to the apical tooth.
Males have distinct fine mesepisternal punctures.
Redescription. FEMALE. Length 5.25–7.10 mm; head length 1.58–1.82 mm; head width 1.70–1.99 mm;
forewing length 4.64–5.00 mm.
Colouration. Head and mesosoma deep blue with occasional green or brassy reflections. Clypeus with
apical 1/3 blackish brown. Antenna dark brown, flagellum with ventral surface dark brown. Tegula dark, reddish
brown. Wing membrane subhyaline, venation and pterostigma reddish brown. Legs brown, medio- and
distitarsi reddish. Metasomal terga blue, with greenish reflections, sterna brown, apical margins reddish
Pubescence. Dull white. Sparse. Head and mesosoma with moderately sparse woolly hairs (1–1.5 OD),
longest on genal beard, metanotum and mesopleuron (2–2.5 OD). Lower paraocular area and gena with
sparse, appressed hairs. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–
2.5 OD). Metasomal terga with sparse, fine setae. T1 acarinarial fan complete dorsally with widely spaced
appressed hairs. T2–T4 with at most a few, scattered appressed hairs at basal margin.
Surface sculpture. Face weakly imbricate, punctation fine. Clypeus polished, basal margin imbricate,
punctation sparse (i=1–3d). Supraclypeal area with punctation moderately sparse (i=1–2d). Lower paraocular
and antennocular areas with punctation moderately dense (i=1–1.5d). Upper paraocular area and frons punctate-
reticulate. Ocellocular area minutely punctate (i=d). Gena weakly lineolate. Postgena imbricate.
Mesoscutum polished, weakly imbricate, punctation fine and deep, sparse medially (1–3d), moderately dense
laterad of parapsidal lines (i≤1.5d) and dense on anterolateral portions (i
Structure. Head wide (length/width ratio = 0.92–0.93). Eyes weakly convergent below (UOD/LOD ratio =
1.17–1.23). Mandible subapical tooth nearly as long as apical tooth. Clypeus ˝ below suborbital tangent, apicolateral
margins weakly convergent. Antennal sockets close (IAD/OAD < 0.5). Frontal line carinate, ending
<2 OD below median ocellus. Gena wider than, or subequal to, eye. Inner metatibial spur pectinate with 3–5
teeth. Metapostnotum moderately elongate (MMR ratio = 1.26–1.33), posterior margin weakly angled onto
posterior surface. Propodeum with oblique carina moderately strong, lateral carina moderately strong, reaching
MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 6.71
mm; head length 1.76 mm; head width 1.81 mm; forewing length 4.94 mm.
Colouration. Head, mesosoma and metasoma bluish green. Flagellum with ventral surface yellowish
brown. Tarsi brownish yellow.
Pubescence. Face below eye emargination with moderately dense tomentum, partially obscuring surface.
Lower paraocular area with dense tomentum. Gena without tomentum. S2 apicomedial, S3 apical half, S4 lateral
and S5 apicolateral portions with moderately dense plumose hairs.
Surface sculpture. Clypeal punctation moderately dense (i=1–2d). Mesepisternal punctation distinct (i=1–
2d). Metanotum rugulose. Metapostnotum completely rugoso-striate. Propodeum with dorsolateral slope and
lateral and posterior surfaces rugose.
Structure. Head moderately wide (length/width ratio = 0.97). Eyes strongly convergent below (UOD/LOD
ratio = 1.57). Clypeus 2/3 below suborbital tangent, apicolateral margins subparallel. Antennal sockets distant
(IAD/OAD > 1.7). Frontal line carinate, ending <2.5 OD below median ocellus. Pedicel shorter than F1. F2
length 2.0X F1. F2–F10 elongate (length/width ratio = 1.69–2.00). Metapostnotum moderately truncate
(MMR ratio = 1.29), posterior margin sharply angled onto posterior surface.
Terminalia. S7 with median lobe clavate, sides concave, apex rounded. S8 with apicomedial margin
weakly convex. Genitalia as in Fig. 91D–F. Gonobase with ventral arms widely separated. Gonostylus small,
dorsal setae elongate. Retrorse lobes elongate, wide, attenuated and recurved apically.
Range. Ontario south to Georgia, west to Kansas
Extracted from Jason Gibbs. 2011. Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini.) Zootaxa.
Lasioglossum (Dialictus) coeruleum (Robertson)
Halictus coeruleus Robertson, 1893: 146. ♀ ♂.
Lectotype. ♀ USA, Illinois, Macoupin Co., Carlinville, 10.iv.1889 (C. Robertson); [INHS: 8806] by W. E. LaBerge (in
Webb 1980). Examined.
Taxonomy. Robertson, 1902b: Chloralictus caeruleus, p. 248 (key); Viereck, 1916: Halictus (Chloralictus) caeruleus,
p. 706; Michener, 1951: Lasioglossum (Chloralictus) coeruleum, p. 1113. (catalogue); Mitchell, 1960: Dialictus
coeruleus ♀♂, p. 387 (redescription, key); Krombein, 1967: Lasioglossum (Dialictus) coeruleum, p. 463
(catalogue); Hurd, 1979: Dialictus coeruleus, p. 1965 (catalogue); Moure & Hurd, 1987: Dialictus coeruleus, p. 95
(catalogue); Pesenko et al. 2000: Evylaeus coeruleus, p. 6 (review); Gibbs, 2010b: Lasioglossum (Dialictus) coeruleum
♀♂, p. 97 (redescription, key).
Diagnosis. Both sexes of L. coeruleum are easily recognisable by their large size (5.3–7.1 mm), body with
deep metallic blue colouration (sometimes with green reflections), sparse metasomal pubescence, and mesepisternal
punctures fine (sometimes obscure in females).
Range. Ontario south to Georgia, west to Kansas. USA: DE, GA, IL, IN, KS, MA, MD, MI, MN, NY, TX, VA,
WI, WV. CANADA: ON, PQ.
DNA Barcode. Available. Multiple sequences.
Lasioglossum coeruleum is known to form primitively eusocial colonies in rotten logs (Stockhammer 1967).