Lasioglossum (Dialictus) floridanum (Robertson)

Gibbs, Jason, 2011, Revision of the metallic Lasioglossum (Dialictus) of eastern North America (Hymenoptera: Halictidae: Halictini), Zootaxa 3073, pp. 1-216 : 92-97

publication ID 10.5281/zenodo.1049595

publication LSID

persistent identifier

treatment provided by


scientific name

Lasioglossum (Dialictus) floridanum (Robertson)


Lasioglossum (Dialictus) floridanum (Robertson)

( Figures 103–107 View FIGURE 103 View FIGURE 104 View FIGURE 105 View FIGURE 106 View FIGURE 107 )

Halictus floridanus Robertson, 1892: 269 . Ƥ.

Lectotype. Ƥ USA, Florida, Inverness, 7.iii. 1891 (C. Robertson); [ INHS: 10232] by W. E. LaBerge (in Webb 1980). Examined.

Dialictus intrepidus Mitchell, 1960: 437 . 3.

Holotype. 3. USA, Georgia, Stone Mountain, 1917; [ CUIC: 4891]. Examined.

Taxonomy. Michener, 1951: Lasioglossum (Chloralictus) floridanum floridanum , p. 1113 (catalogue); Mitchell, 1960: Dialictus pilosus floridanus , p. 414 (key, tax. char.); Krombein, 1967: Lasioglossum (Dialictus) pilosum floridanum , p. 465 (catalogue); Moure and Hurd, 1987: Dialictus pilosus floridanus , p. 123 (catalogue); Gibbs, 2010 b: Lasioglossum (Dialictus) floridanum , p. 258 (tax. notes, synonymy).

Diagnosis. Female L. floridanum can be recognised by the following diagnostic combination: head elongate (length/ width ratio = 1.08–1.10) ( Fig. 103 View FIGURE 103 B); clypeus with apicolateral margins subparallel ( Fig. 103 View FIGURE 103 B); mesoscutal punctures dense (i<d) ( Fig. 104 View FIGURE 104 ); metapostnotal rugae fine, relatively indistinct from surrounding microsculpture; metasomal terga metallic; T 2 without apical fringe medially; and T 3 with sparse tomentum apically. They are most similar to L. pilosum , which has strong metapostnotal rugae, T 2 with apical fringe medially, and dense tomentum obscuring the disc of T 3.

Male L. floridanum can be recognised by the head elongate (length/width ratio = 1.17) ( Fig. 105 View FIGURE 105 B); eyes strongly convergent below (UOD/LOD ratio = 1.54); clypeus with distal margin brown, sometimes yellow; mesoscutal punctures dense ( Fig. 106 View FIGURE 106 ); metapostnotal rugae weak; and metasomal terga metallic, punctation dense and distinct. They are most similar to L. pilosum and L. succinipenne , both of which have clypeus with yellow distal band and metapostnotal rugae.

Redescription. FEMALE. Length 4.70–6.66 mm; head length 1.73–1.92 mm; head width 1.60–1.75 mm; forewing length 3.93–4.36 mm.

Colouration. Head and mesosoma pale green to golden green. Clypeus with apical half blackish brown. Supraclypeal area bronze. Antenna dark brown, flagellum with ventral surface reddish brown at apex. Tegula amber. Wing venation and pterostigma pale amber. Legs brown, except protibial base and medio- and distitarsi reddish brown. Metasomal terga golden green, sterna brown, apical margins pale, translucent yellow.

Pubescence. Dull white to yellowish. Dense. 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 and gena with subappressed tomentum sometimes partially obscuring surface. Mesoscutum with dense hairs. Propodeum with moderately dense plumose hairs on lateral and posterior surfaces (2–2.5 OD). Metasomal terga with dense, fine hairs. T 1 acarinarial fan complete and dense. T 1 apicolateral portion with tomentum. T 2 basal and lateral portions, T 3 basal, lateral and apicolateral portions, T 4 –T 5 with dense tomentum obscuring surface. T 2 –T 4 apical margins with moderately dense fringes.

Surface sculpture. Face imbricate, punctation fine. Clypeus polished, imbricate, punctation (i= 1–2 d). Supraclypeal area with punctation moderately dense (i= 1–1.5 d). Lower paraocular and antennocular areas with punctation dense (i≤d).

Upper paraocular area and frons punctate-reticulate. Ocellocular area minutely punctate-reticulate. Gena and postgena lineolate. Mesoscutum tessellate-imbricate, punctation dense on medial portion of disc (i<d), punctate-reticulate mesad and laterad of parapsidal line and on anterolateral portion. Mesoscutellum weakly imbricate, submedial punctation moderately dense (i= 1–1.5 d). Axilla punctate. Metanotum ruguloso-imbricate. Preëpisternum rugulose. Hypoepimeral area rugulose. Mesepisternum weakly rugulose. Metepisternum with upper half rugoso-carinulate, lower half imbricate. Metapostnotum with weak rugae, posterior margin tessellate. Propodeum with dorsolateral slope rugulose, lateral and posterior surfaces rugulose-tessellate. Metasomal terga weakly coriarious, punctation moderately dense throughout (i= 1–1.5 d).

Structure. Head elongate (length/width ratio = 1.08–1.10). Eyes convergent below (UOD/LOD ratio = 1.20–1.26). Clypeus ½ below suborbital tangent, apicolateral margins weakly convergent. Antennal sockets close (IAD/OAD <0.5). Frontal line carinate, ending 2 OD below median ocellus. Gena narrower than eye. Inner metatibial spur pectinate with 4 branches. Metapostnotum truncate (MMR ratio = 1.28–1.38), posterior margin weakly angled onto posterior surface. Propodeum with oblique carina fine, lateral carina weak, not reaching dorsal margin.

MALE. Similar to female except for the usual secondary sexual characters and as follows. Length 5.51 mm; head length 1.78 mm; head width 1.51 mm; forewing length 4.05 mm.

Colouration. Labrum brownish yellow. Mandible brownish yellow. Clypeus distal margin yellowish brown (rarely brown). Flagellum with ventral surface ferruginous. Legs brown, except tibial bases and apices and tarsi brownish yellow.

Pubescence. Moderately dense. Face below eye emargination with tomentum obscuring paraocular area, partially obscuring clypeus and supraclypeal area. T 1 acarinarial area with sparse fan of appressed hairs. T 2 –T 3 basolaterally and T 4 basally with sparse tomentum. S 2 –S 3 entirely and S 4 laterally with posteriorly directed hair patches (1–1.5 OD).

Surface sculpture. Clypeal punctation moderately dense (i= 1–2 d). Propodeum with dorsolateral slope and lateral and posterior surfaces rugulose. Metasomal terga punctation deep, distinct.

Structure. Head very elongate (length/width ratio = 1.17). Eyes strongly convergent below (UOD/LOD ratio = 1.54). Clypeus 2 / 3 below suborbital tangent, apicolateral margins subparallel. Antennal sockets distant (IAD/OAD = 1.0). Frontal line carinate, ending 2 OD below median ocellus. Pedicel shorter than F 1. F 2 length 1.5 X F 1. F 2 –F 10 moderately elongate (length/width ratio = 1.33–1.50). Metapostnotum truncate (MMR ratio = 1.45), posterior margin weakly angled onto posterior surface.

Terminalia . S 7 with median lobe clavate, apex rounded ( Fig. 107 View FIGURE 107 ). S 8 with apicomedial margin weakly convex ( Fig. 107 View FIGURE 107 ). Genital capsule as in Fig. 107 View FIGURE 107 . Gonobase with ventral arms narrowly separated. Volsella roughly ovoid. Gonostylus small, dorsal setae elongate. Retrorse lobe elongate, strongly attenuated apically.

Range. Wisconsin south to Florida, west to Texas ( Fig. 102 View FIGURE 102 ). USA: FL, GA, IN, MD, NC, OK, SC, TX, WI.

Additional specimens examined. USA: FLORIDA: 1 Ƥ Union Co., 3.i. 1930 (R.B. Howard); [ CUIC]; 15 ƤƤ paratypes, Inverness, (C. Robertson); [ INHS]; 1 Ƥ Inverness, (C. Robertson); [ UCMC]; GEORGIA: 3 ƤƤ 13 Pavo, N 30.941 W083.708, 2005 (A. Zayed); [ PCYU]; INDIANA: 1 Ƥ Porter Co., Indiana Dunes N.L., Ogden Dunes, N 41 ˚ 37 ʹ0ʹʹ W 87 ˚ 11 ʹ 51 ʹʹ, 2004 (R. Grundel); 1 Ƥ Porter Co., Indiana Dunes N.L., Ogden Dunes, N 41 ˚ 37 ʹ0ʹʹ W 87 ˚ 11 ʹ 51 ʹʹ, 23.vii. 2003 (R. Grundel); 2 ƤƤ Jasper Co., Tefft Savanna, N 41 ˚ 9 ʹ 25 ʹʹ W 86 ˚ 58 ʹ 41 ʹʹ, 28.iv. 2004 (R. Grundel); 2 ƤƤ Jasper Co., Tefft Savanna, N 41 ˚ 9 ʹ 25 ʹʹ W 86 ˚ 58 ʹ 41 ʹʹ, 14.vii. 2003 (R. Grundel); [ IDNL]; 1 Ƥ Jasper Co., Nipsco, 17.vii. 2001 (R.P. Jean); 1 Ƥ Newton Co., Conrad, 2003 (R.P. Jean); 1 Ƥ Starke Co., Ober, 2001 (R.P. Jean); [ PCYU]; MARY- LAND: 1 Ƥ Worcester Co., Pocomoke River S.F., sand dune, N 38.23882 W075.58212, 18–20.ix. 2009 (J. & F. Frye); [ CUIC]; NORTH CAROLINA: 18 ƤƤ Hoke Co., Fort Bragg Mil. Res., 10– 1998 (B.N. Danforth); [ CUIC]; 1 Ƥ 13 Spout Spring, 25.x. 1952 (T.B. Mitchell); [ CUIC]; 3 ƤƤ S. of Lillington, 29.iii. 1945; [ NCSU]; SOUTH CAROLINA: 1 Ƥ Aiken, 1957 (J.R. Vockeroth); 1 Ƥ Hilton Head Is., 11–23.vii. 1965 (H.F. Howden); [ CNC]; 1 Ƥ Chesterfield Co., N 34.5836 W080.24529, 18.v. 2006 (S.W. Droege); 3 ƤƤ Chesterfield Co., N 34.5305 W080.2223, 6–8.ix. 2006 (S.W. Droege); [ PCYU]; TEXAS: 1 Ƥ 13 Bastrop Co., Bastrop S.P., 3.viii. 1988 (J.L. Neff); [ CTMI]; 1 Ƥ Donley Co., Lake McClellan, 28.vii. 1972 (G.C. Eickwort); 1 Ƥ Nacogdoches Co., N 31.5011 W094.7839, 16– 2010 (C. Adams); [ CUIC]; WISCONSIN: 1 Ƥ Monroe Co., N 44.1465 W090.6948, 15–19.vii. 2010 (H. Gaines).

Floral records. ASTERACEAE : Chrysopsis , Cirsium , Coreopsis palmata, “ Haplopappus ”, Pyrrhopappus , Silphium ; ERICACEAE : Vaccinium ; EUPHORBIACEAE : Euphorbia corollata ; FABACEAE : Amorpha , Baptisia , Galactia ; ROSACEAE : Photinia , Crataegus , Rubus ; SCROPHULARIAE : Aureolaria pedicularia ; UNCERTAIN: “ Gerardia ”.

DNA Barcode. Available. Multiple sequences.

Comments. Uncommon.

Mitchell (1960) and others have considered L. floridanum to be a subspecies of L. pilosum . The degree of morphological differentiation between L. floridanum and L. pilosum is similar to that between other species of L. ( Dialictus ) and DNA barcodes distinguish the two species. As such, full species-level status has been given to L. floridanum (see Gibbs 2010 b).


Illinois Natural History Survey


Cornell University Insect Collection


University of Colorado Museum


The Packer Collection at York University


North Carolina State University Insect Museum


Canadian National Collection of Insects, Arachnids, and Nematodes


Department of Natural Resources, Environment, The Arts and Sport














Lasioglossum (Dialictus) floridanum (Robertson)

Gibbs, Jason 2011

Dialictus intrepidus

Mitchell 1960: 437

Halictus floridanus

Robertson 1892: 269