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Identification Summary: Large; nest parasite; head very large, broad and cheeks extremely wide and usually with a strong angle to their rim rather than the normal smooth outline; most similar to L. cephalotes but shape of mandible wider.
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 4.5-5.0 mm.; head and thorax dark bluish-green, abdomen brownish piceous; pubescence short and thin, entirely pale; head much broader than long; clypeus flat, short and very broad; eyes very slightly nearer to each other than to eyes; mandibles elongate, sickle-shaped, without teeth; labrum with a low but distinct, basal, median tubercle; cheeks very broad, with a rounded posterior angle opposite lower portion of eye; face below ocelli rather dull, punctures very fine and close but quite distinct, becoming obscure and sparse on the more shining vertex, cheeks microscopically striate, becoming quite smooth and shining below; hypostomal carinae rather strongly divergent apically; lower half of lace shining, with well separated but deep and distinct punctures, those on the supraclypeal area and clypeus very fine and sparse, surface shining; scutum and scutellum somewhat shining, punctures very fine, irregularly scattered, rather sparse in center of disc; pleura rather dull, without distinct punctures; dorsal area of propodeum quite completely striate, the lateral faces more shining; wings subhyaline, veins and stigma testaceous; tegulae brownish-testaceous; legs more ferruginous basally, becoming slightly more yellowish apically; abdominal terga shining, basal tergum without distinct punctures, 2nd and following terga becoming somewhat more distinctly and closely but still minutely punctate, terga 3 and 4 largely devoid of tomentum.
MALE�Length 4.5-6.0 mm.; head and thorax bluish-green, abdomen brownish-piceous pubescence entirely white, rather copious on head and thorax; length and breadth of head subequal; clypeus rather fiat, somewhat broader than long; eyes rather strongly convergent below; antennae slightly nearer eyes than to each other, basal segment of flagellum short, subequal to pedicel, the following segments only slightly longer than broad; cheeks sub- equal to eyes in width; face below ocelli rather dull, punctures rather fine and close, but distinct, becoming more obscure on vertex, cheeks striate posteriorly, becoming somewhat shining below; hypostomal carinae slightly divergent apically; scutum and scutellum somewhat shining, very finely punctate, punctures close except in center of disc; pleura dull, finely rugoso-striate; dorsal area of propodeum quite coarsely and completely striate, the lateral faces roughened but somewhat shining; wings subhyaline, veins and stigma brownish-testaceous; tegulae more ferruginous; basal segments of leg piceous, tibiae somewhat yellowish basally and apically, and all tarsi rather distinctly yellow; abdominal terga shining, punctures very fine but quite distinct, rather uniformly distributed, slightly separated but not sparse, apical margins of the terga narrowly depressed, smooth and shining.
DISTRIBUTION�Minnesota, Michigan and Maryland, south to Tennessee and Georgia; April to September.
FLOWER RECORDS�Cucurbita, Erigeron, Koellia, Rhus, Salts and Solidago. Recorded by Robertson (1929) on Aster, Gnaphalium, Gonolobus, Salts, Taraxacum, Zanthoxylum and Zizia.
Retrieved from: Gibbs, J. 2010. Revision of the metallic species of Lasioglossum (Dialictus)in Canada (Hymenoptera, Halictidae, Halictini). Zootaxa; 2591, 261-265
Halictus platyparius Robertson, 1895: 117. ♀.
Lectotype. ♀ USA, Illinois, Carlinville (C. Robertson); [INHS: 179,614] by W.E. LaBerge.. Examined.
Taxonomy. Robertson, 1901: Paralictus platyparius, p. 229 (generic description); Michener, 1951: Lasioglossum
(Paralictus) platyparium, p. 1119 (catalogue); Mitchell, 1960: Paralictus platyparius ♀♂, p. 448
(redescription); Krombein, 1967: Lasioglossum (Paralictus) platyparium, p. 467 (catalogue); Paralictus
platyparius, p. 1974 (catalogue); Moure & Hurd, 1987: Paralictus platyparius, p. 143 (catalogue).
Diagnosis. See the diagnosis for L. asteris.
Redescription. FEMALE. Length 4.58�5.80 mm; head length 1.39�1.51 mm; head width 1.63�1.80 mm;
forewing length 3.48�3.84 mm
Colouration. Head and mesosoma very dull metallic bluish green. Antenna dark brown, flagellum with
ventral surface reddish brown. Tegula dark reddish brown to dark amber. Wing membrane dusky, venation
and stigma dark amber. Legs brown, medio- and distitarsi reddish brown. Metasoma dark brown, terga and
sterna with apical margins translucent brownish yellow.
Pubescence. Dull white. Sparse throughout. Head and mesosoma with moderately sparse woolly hairs (1�
1.5 OD), longest on genal beard, metanotum and mesopleuron (2�2.5 OD). Face without appressed hairs. Pronotal
collar without dense tomentum. Propodeum with moderately dense plumose hairs on lateral and posterior
surfaces (2�2.5 OD). Mesofemoral and mesotibial combs dense but short relative to non-parasitic species.
Metafemoral scopa reduced relative to nest-building species, only a few elongate hairs curving above ventral
surface. Penicillus greatly reduced, indistinguishable from other hairs. Metasoma with moderately sparse, fine
setae. T1 acarinarial fan sparse, incomplete with dorsal opening greater than width of lateral appressed hair
patches. T2�T3 basolaterally and T4 entirely with very sparse tomentum. Sternal hairs erect, posteriorly
directed (2�3 OD). T2 apicolateral and T3�T4 apical margins with very sparse fringes.
Surface sculpture. Face polished, weakly imbricate, punctation fine. Clypeal punctation sparse (i=1�5d).
Supraclypeal, lower paraocular and antennocular areas with punctation moderately sparse (i=1�3d). Upper
paraocular area and frons punctation dense (i≤d). Ocellocular area punctate (i=1�1.5). Gena faintly lineolate.
Postgena faintly imbricate. Mesoscutum weakly imbricate, more polished posteriorly, punctation sparse
between parapsidal lines (i=1�4d), moderately sparse laterad of parapsidal lines (i=0.5�1.5d) and dense on
anterolateral portions (i≤d). Mesoscutellum polished, submedial portion virtually impunctate. Axilla punctate.
Metanotum imbricate. Pre�pisternum rugulose. Hypoepimeral area imbricate. Mesepisternum dorsal half
weakly rugulose, ventral half imbricate. Metepisternum dorsal half rugoso-striate, ventral half imbricate.
Metapostnotum with longitudinal striae not reaching posterior margin, posterior surface imbricate. Propodeum
with dorsolateral slope and lateral surface imbricate, posterior surface tessellate. Metasomal terga polished
except apical impressed areas faintly coriarious, punctation on basal halves (i=1�1.5d), apical half
obscurely punctate (i=1.5�2.5d).
Structure. Head enormous, very wide (length/width ratio = 0.84�0.85). Eyes weakly convergent (UOD/
LOD ratio = 1.07�1.09). Labrum enlarged and flattened with distinct basal tubercle, apical process without
dorsal keel. Mandibles large, scythe-like, with minute subapical angle. Clypeus 1/3 below suborbital tangent,
apicolateral margins widely convergent. Antennal sockets distant (IAD/OAD > 0.75). Frontal line carinate,
ending 2.5 OD below median ocellus. IOD subequal to OOD. Gena huge, 1.5 times as wide as eye. Pronotal
dorsolateral angle acute. Pronotal ridge uninterrupted. Basitibial plate with posterior carina weak. Inner metatibial
spur pectinate with 3�4 short teeth. Metapostnotum truncate (MMR ratio = 1.32�1.43), posterior margin
weakly angled onto posterior surface. Propodeum with oblique carina very weak, lateral carina weak, not
reaching dorsal margin. T5 medial specialized area reduced in size relative to non-parasitic species.
MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 4.64�
5.25 mm; head length 1.30�1.42 mm; head width 1.34�1.44 mm; forewing length 2.93�3.66 mm.
Colouration. Labrum, mandible, flagellum ventral surface, Tibial bases and apices, and tarsi yellow to
brownish yellow.
Pubescence. Face below eye emargination with sparse tomentum, partially obscuring lower paraocular
area, nearly absent from clypeus and supraclypeal area. S2�S5 lateral portions with moderately spare plumose
hairs (1�1.5 OD).
Surface sculpture. Lower paraocular and supraclypeal areas densely punctate (i≤d). Frons reticulate, punctation
moderately sparse between parapsidal lines (i=1�2.5d), dense laterad of parapsidal lines and on anterolateral
portions (i≤d). Ventral mesepisternum sometimes obscurely punctate. Metapostnotum crescentic,
completely rugoso-striate. Propodeum with dorsolateral slope and posterior surface rugulose. Metasomal
terga distinctly punctate (i=1�2d), apical impressed margin impunctate.
Structure. Head wide (length/width ratio = 0.95�0.96). Eyes strongly convergent below (UOD/LOD ratio
= 1.33�1.41). Clypeus 2/3 below suborbital tangent, apicolateral margins convergent. Antennal sockets distant
(IAD/OAD > 1.1). Frontal line carinate, ending 2 OD below median ocellus. IOD subequal to OOD. Pedicel
subequal to F1. F2 length 1.6�1.7X F1. F2�F10 moderately short (length/width ratio = 1.25�1.42). Pronotum
dorsolateral angle orthogonal. Metapostnotum moderately elongate (MMR ratio = 1.08�1.30), posterior margin
sharply angled onto posterior surface.
Terminalia. S7 with median lobe widely acuminate, apex rounded (Fig. 185D). S8 with apicomedial margin
weakly convex (Fig. 185D). Genitalia as in Fig. 185D�E. Gonobase with ventral arms narrowly separated.
Gonostylus small, dorsal setae elongate. Retrorse lobe wide, moderately elongate, weakly attenuated apically.
Range. Ontario south to Georgia, Louisiana and west to Minnesota (Fig. 186).
Additional material examined. USA: DISTRICT OF COLUMBIA: 1♂ N38.87972 W077.033, 4�
5.x.2004 (E. Keto); 2♀♀ N38.8883 W077.045, 6�7.x.2004 (E. Keto); 2♂♂ N38.895 W077.04583, 6�7.x.2004
(E. Keto); 3♂♂ N38.886 W077.03416, 18�19.x.2004 (E. Keto); 1♂ N38.886 W077.03694, 18�19.x.2004 (E.
Keto); [PCYU]; GEORGIA: 1♀ Jasper Co., Oconee N.F., 16.v.2008 (J. Hanula & S. Horn); [JHRC]; MARYLAND:
3♀♀ Anne Arundel Co., N38.858 W76.6866, 2.iv.2002 (S.W. Droege); 1♀ Pr. George�s Co., N39.037
W076.8719, 18�19.iv.2006 (Riegel & Walker); 1♀ Pr. George�s Co., N39.0294 W076.9268, 22.viii.2004 (N.
Allen); NORTH CAROLINA: 1♂ Junaluska Meadow, N35.54289 W082.9566, 7.viii.2006 (J. Gibbs); WEST
VIRGINIA: 1♀ Jefferson Co., Shepherdstown National Conservation Training Center, 7.iv.1999 (S. Droege);
[PCYU]; WISCONSIN: 1♂ Marinette Co., N45.2441 W87.81875, 28.vii.2005 (J. Watson); [ARC].
Floral records. ANACARDIACEAE: Rhus, APIACEAE: Zizia aurea, ASCLEPIADACEAE: Cynanchum
laeve, ASTERACEAE: Erigeron, Gnaphalium �polycephalum�, Solidago nemoralis, Symphyotrichum
pilosum, S. lateriflorum, S. ericoides, Taraxacum, CUCURBITACEAE: Cucurbita, LAMIACEAE:
Pycnanthemum, RUTACEAE: Zanthoxylum americanum, SALICACEAE: Salix cordata.
Comments. Uncommon. This is a parasitic species. Host species unknown. No Canadian material has
been examined. A specimen from New York state has been reported (Fetridge et al. 2008). This in combination,
with the material from Wisconsin, make the occurrence of this species in Ontario seem likely.
Extracted from Jason Gibbs. 2011. Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini.) Zootaxa.
Lasioglossum (Dialictus) platyparium (Robertson)
Halictus platyparius Robertson, 1895: 117. ♀.
Lectotype. ♀ USA, Illinois, Macoupin Co. Carlinville, 18.v.1887 (C. Robertson); [INHS: 3995] by W. E. LaBerge (in
Webb 1980). Examined.
Taxonomy. Robertson, 1901: Paralictus platyparius, p. 229 (generic description); Michener, 1951: Lasioglossum (Paralictus)
platyparium, p. 1119 (catalogue); Mitchell, 1960: Paralictus platyparius ♀♂, p. 448 (redescription); Krombein,
1967: Lasioglossum (Paralictus) platyparium, p. 467 (catalogue); Paralictus platyparius, p. 1974 (catalogue); Moure &
Hurd, 1987: Paralictus platyparius, p. 143 (catalogue); Gibbs, 2010b: Lasioglossum (Dialictus) platyparium ♀♂, p. 261
(redescription, key)
Diagnosis. Female L. platyparium can be recognised by the following diagnostic combination: scopa absent; gena
wider than eye; mandible large, converging to point only near apex, distinct preapical tooth absent; labrum with distinct
basal tubercle, apical process flat, dorsal keel absent (Fig. 6B); and metapostnotum rugoso-carinulate. They are similar to
L. cephalotes and L. rozeni. Female L. rozeni have a narrow mandible that is evenly convergent along its entire length and
lacks a distinct basal tubercle on the labrum. Female L. cephalotes lack a distinct basal tubercle on the labrum and have a
smooth metapostnotum without evident rugae.
Male L. platyparium can be recognised by head wide (length/width ratio = 0.95�0.96), dorsolateral angle of pronotum
acute, pronotal collar weak, and mesepisternum rugulose.
Range. Ontario south to Georgia, Louisiana and west to Minnesota. USA: DC, GA, IL, KS, LA, MD, MN, MO, NC,
PA, WV, WI. CANADA: ON.
DNA Barcode. Available. Multiple sequences.
Comments. Uncommon.
Lasioglossum platyparium is presumed to be a social parasite of nest-building Dialictus. It is perhaps the most commonly
collected of the parasitic L. (Dialictus) but its host species remains unknown.
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