Lasioglossum Curtis 1833
Creators: name: Gardner, Joel
name: Gibbs, Jason
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Halictidae
Lasioglossum

description: Key to Nearctic Lasioglossum groups with enlarged tegula
1. Head and mesosoma black to brown ................................................................................................ 2
– Head and mesosoma metallic golden, green, or blue ....................................................................... 3
2. Mesepisternum rugose .............................................. L. (Hemihalictus) kincaidii (Cockerell, 1898)
– Mesepisternum imbricate ..................................... L. (Hemihalictus) glabriventre (Crawford, 1907)
3. Metasoma with no appressed tomentum in either sex (but with abundant simple setae); S2–S4 with long (2–4 OD), dense, scopa-like pubescence in males ..................................................................... ............................. L. (Dialictus) knereri Gibbs, 2010 (atypical forms only known from California)
– Metasoma with some appressed tomentum at least on T2–T3 basolateral areas in females; S2–S4 with shorter (1–2 OD) and sparser pubescence in males, not scopa-like ......................................... 4
4. T1 with lateral tomentum (except in some males); clypeus projecting more than 50% below suborbital tangent; propodeum oblique carina absent in both sexes ................................................................... .......................................................................................... L. (Dialictus) perdifficile species complex
– T1 without lateral tomentum in either sex; clypeus projecting about 50% below suborbital tangent; propodeum oblique carina present in females (but may be fine and difficult to distinguish from background surface sculpture) ........................................ L. (Dialictus) gemmatum species complex
Key to females
1. Mesoscutum with appressed, fine, stubble-like setae less than 0.25 OD long, appearing shaved, and erect plumose setae about 1 OD long or less, these setae very sparse (each seta separated by about its length from the one nearest it, with some gaps about a seta’s length wide visible in lateral view) (Fig. 78A–B); mesoscutum golden-green to coppery, contrasting with blue to blue-green propodeum; size very small (ITS 0.67–0.77 mm); metasoma black .................................................................... 2
– Mesoscutum with appressed, fine setae 0.25–0.5 OD long and erect plumose setae about 1 OD long, these setae dense (each seta within its length from the one nearest it, with no gaps wider than half a seta’s length visible in lateral view) (Fig. 78C–D); mesoscutum usually concolourous with propodeum; size larger (ITS normally> 0.77 mm, except in L. gloriosum sp. nov., L. indagator sp. nov., and L. rufodeludens sp. nov., in which the metasoma is red-orange) ................................. 3
2. Tegula sparsely punctate (IS = 1–4 PD) at least laterally, not exceeding posterior margin of mesoscutum in dorsal view, with inner posterior margin straight, coming to a blunt angle posteriorly (Fig. 79A); apical rims of T1–T3 minutely punctate (Fig. 80A) (deserts of southern United States and northern Mexico) .................................................................................................... L. perparvum (Ellis, 1914)
– Tegula densely punctate (IS <1 PD), exceeding posterior margin of mesoscutum in dorsal view by almost 1 OD, with inner posterior margin concave and a rounded projection reaching axilla posteriorly (Fig. 79B); apical rims of T1–T3 impunctate (Fig. 80B) (Neotropical Mexico, rarely occurring north to United States border) ................................................................................ L. magnitegula sp. nov.
3. Tegula impunctate except on extreme anterior margin (Fig. 81A) ................................................... 4
– Tegula with at least a few distinct punctures medially, usually many (Fig. 81B–C) ........................ 7
4. Tegula dark brown; mesoscutum coarsely punctate (punctation similar to mesepisternum) ............. ......................................................................................................................... L. profundum sp. nov.
– Tegula yellow-orange; mesoscutum more finely punctate (punctures smaller than those of mesepisternum) ................................................................................................................................. 5
5. Mesoscutum and mesepisternum completely dull, tessellate to imbricate; metasoma entirely redorange (eastern Texas, Nuevo Leon, and Tamaulipas) ................................ L. rufodeludens sp. nov.
– Mesoscutum lateral and posterior margins and/ or mesepisternum shiny with at most weak microsculpture (rarely both dull); at least basal half of discs of metasomal terga reddish brown to black (apical areas may be red-orange or black) .............................................................................. 6
6. Postgena smooth and shiny (as in Fig. 82A) (Chihuahuan and Sonoran Deserts) ............................. ............................................................................................................................. L. deludens sp. nov.
– Postgena dull, lineolate (as in Fig. 82B) (Florida Keys and Bahamas) .............................................. ................................................................................................. L. surianae (Mitchell, 1960) [in part]
7. Mesoscutum, preëpisternum, mesepisternum, and hypoepimeron margins fringed with appressed tomentum (Fig. 83A); metepisternum covered in dense tomentum obscuring the surface; metanotum median third covered in dense pubescence obscuring the surface (Fig. 83A); tegula and metasoma bright red-orange .............................................................................................................................. 8
– Mesoscutum and pleura without appressed tomentum (except sometimes mesoscutum anterolateral margins or metepisternum with sparse tomentum not obscuring the surface) (Fig. 83B); metanotum with dense pubescence limited to anterior margin (Fig. 83B); tegula and metasoma usually black to brown (if red-orange, then lacking the other characters) .................................................................. 9
8. Mesepisternum with most punctures separated by half a puncture diameter or less (IS <0.5 PD) (Fig. 84A); tegula outer margin densely punctate (IS ≤ 1 PD) (Nevada, Utah, and northern New Mexico) ............................................................................................................. L. gloriosum sp. nov.
– Mesepisternum with most punctures separated by up to one puncture diameter or slightly more (IS ≤1 PD) (Fig. 84B); tegula outer margin sparsely punctate (IS = 1–3 PD) (southern Arizona, New Mexico, and Texas) ............................................................................................ L. indagator sp. nov.
9. T2–T3 usually each slightly convex with apical rim distinctly downcurved in lateral view (Fig. 85A); T3 usually with dense and complete subapical band of tomentum (Fig. 86A); disc of T2 with deep and dense punctures (IS ≤ 1 PD) reaching premarginal line and contrasting with largely impunctate apical rim (Fig. 86A) (Colorado to Veracruz) .......................................... L. coactus (Cresson, 1872)
– T2–T3 each flat in lateral view and apical rim continuous with contour of disc (Fig. 85B); T3 without subapical band of tomentum or this band sparse and broadly interrupted medially (except in L. stictaspis and L. tegulariforme, in which the disc of T2 has finer and sparser punctures (IS = 1–3 PD) either becoming inconspicuous near premarginal line or extending onto apical rim) (Fig. 86B) ............ 10
10. Tegula relatively large (maximum length more than half ITS and reaching or exceeding posterior margin of mesoscutum in dorsal view), densely punctate throughout (IS <1 PD), and usually with inner posterior margin deeply concave, forming a broadly rounded posterior projection about the size of 0.5–1 lateral OD (Fig. 87A) (United States west of ~99° and Mexico) ......................................11
– Tegula relatively small (maximum length about half ITS or less and at most reaching posterior margin of mesoscutum in dorsal view), more sparsely punctate medially (IS ≥ 1 PD), and with inner posterior margin straight or weakly concave, forming a sharp posterior angle or point smaller than 0.5 lateral OD (Fig. 87B) (if tegula larger or more densely punctate, then occurring in United States east of ~99°) .................................................................................................................................... 17
11. Metapostnotum smooth with fine, subparallel rugae and completely dull due to fine reticulate microsculpture (Fig. 88A) .............................................................................................................. 12
– Metapostnotum roughened with strong, usually anastomosing rugae (except usually subparallel in L. gaudiale) and shiny basally between rugae due to weak microsculpture (Fig. 88B) ................. 13
12. Face slightly longer on average (length/width ratio 0.8–0.85) (Fig. 89A); mesepisternum densely punctate (IS <1 PD) and usually shiny; mesoscutum uniformly dull due to strong tessellate microsculpture; in Nearctic region, T1–T2 apical rims distinctly punctate with no change in sculpture across premarginal line (impunctate in Neotropics) ................. L. pseudotegulare (Cockerell, 1896)
– Face slightly shorter on average (length/width ratio 0.77–0.84) (Fig. 89B); mesepisternum usually dull or more sparsely punctate (with some IS ≥1 PD) and/or mesoscutum shiny at least on lateral and posterior margins; T1–T2 apical rims impunctate or punctures much sparser and finer than on discs ........................................................................................ L. stictaspis species complex [in part]
13. T1 disc with impunctate median line 1 OD wide or slightly less (Fig. 90A) ..................................... ..................................................................................................... L. tegulariforme (Crawford, 1907)
– T1 disc evenly punctate throughout (Fig. 90B) .............................................................................. 14
14. T1 disc punctures very fine and sparse (IS = 1–4 PD), much sparser than punctures in T2 basal half, or if similar, then all punctures very fine (no wider than fine setae arising from them) and somewhat obscured by coriarious microsculpture on T1–T2 discs (Fig. 91A) ....... L. stictaspis species complex [in part]
– T1 disc punctures distinct and moderately dense (IS = 1–2 PD), similar to punctures in T2 basal half; T1–T2 shiny except sometimes coriarious on T1 anterior slope or T2 apical rim (Fig. 91B) ........ 15
15. T1 anterior slope usually dulled by strong coriarious microsculpture (as in Fig. 92A); mesoscutum very densely and finely punctate (posterior half with no IS>1 PD and 4–5 punctures present between posterior end of parapsidal line and lateral edge of mesoscutum) (as in Fig. 93A); T3 usually with sparse tomentum throughout disc ......................................... L. helianthi (Cockerell, 1916) [in part]
– T1 anterior slope shiny, mirror-smooth, with at most weak microsculpture not dulling surface (Fig. 92B); mesoscutum more sparsely or coarsely punctate (posterior half with IS = 1–3 PD in centre or only 2–3 punctures present between posterior end of parapsidal line and lateral edge of mesoscutum, except sometimes in L. angelicum sp. nov.) (Fig. 93B); T3 with tomentum limited to basal band and, at most, a thin, sparse subapical band which is broadly interrupted medially ...... 16
16. Gena about as wide as eye in lateral view; metapostnotum rugae usually subparallel and not reaching posterior margin (Fig. 94A); scutellum often very coarsely and sparsely punctate in comparison to mesoscutum posterior margin (IS = 1–2 PD) (Fig. 94A) .... L. gaudiale (Sandhouse, 1924) [in part]
– Gena narrower than eye in lateral view; metapostnotum rugae usually anastomosing and reaching posterior margin (as in Fig. 94B); scutellum finely and densely punctate (IS <1 PD except sometimes submedially), similar to mesoscutum posterior margin (as in Fig. 94B) ......... L. angelicum sp. nov.
17. Tegula inner posterior margin straight or nearly so and clearly not reaching posterior margin of mesoscutum in dorsal view (Fig. 95A) ........................................................................................... 18
– Tegula inner posterior margin concave or sinuous and reaching posterior margin of mesoscutum in dorsal view (Fig. 95B) .................................................................................................................... 21
18. Frons above frontal carina dull, reticulate, with no distinct interspaces between punctures (Fig. 96A) (United States west of Rocky Mountains and Mexico) .................................................................. 19
– Frons above frontal carina shiny due to narrow interspaces between punctures (Fig. 96B) (Florida and Bahamas) .................................................................................................................................. 20
19. T1–T3 apical rims usually deeply and distinctly punctate, similar to discs (Fig. 97A); postgena anterior half smooth, shiny or imbricate (as in Fig. 82A); T2–3 with sparse basal bands of tomentum not obscuring the surface underneath and much narrower medially than laterally (Fig. 97A) .......... ......................................................................................................................... L. holzenthali sp. nov.
– T1–T3 apical rims impunctate (Fig. 97B); postgena anterior half lineate (as in Fig. 82B); T2–3 with dense basal bands of tomentum obscuring the surface underneath and about as wide medially as laterally (Fig. 97B) ............................................................................ L. diabolicum sp. nov. [in part]
20. Tegula and metasoma dark brown to black ........................................... L. lepidii (Graenicher, 1927)
– Tegula and metasoma reddish brown to orange ...................... L. surianae (Mitchell, 1960) [in part]
21. Mesepisternum with distinct round punctures; surface often shiny (Fig. 98A) ............................. 22
– Mesepisternum punctures either indistinct or so crowded (IS = 0 PD) that most are polygonal, not round; surface dull, imbricate or rugulose (Fig. 98B) .................................................................... 27
22. T1 disc punctures very fine and sparse (IS = 1–4 PD), much sparser than punctures in T2 basal half, or if similar, then all punctures very fine (no wider than fine setae arising from them) and somewhat obscured by coriarious microsculpture on T1–T2 discs (Fig. 91A) ............................................... 23
– T1 disc punctures distinct and moderately dense (IS = 1–2 PD), similar to punctures in T2 basal half; T1–T2 discs shiny or with microsculpture not obscuring the punctures (Fig. 91B) ...................... 25
23. Mesepisternum punctures similar in size and density to those of hypoepimeron (Fig. 99A); tegula sparsely punctate medially (IS = 1–3 PD); metapostnotum roughened with strong rugae and shiny basally between rugae due to weak microsculpture (as in Fig. 88B) (east of Rocky Mountains) ............................................................................. L. ellisiae (Sandhouse, 1924) [in part]
– Mesepisternum punctures slightly larger and sparser than those of hypoepimeron (Fig. 99B), or if similar, then occurring west of Rocky Mountains; tegula often densely punctate medially (IS ≤ 1 PD); metapostnotum often smooth with fine rugae and completely dull due to fine reticulate microsculpture (as in Fig. 88A) ............................................................................................................................... 24
24. Tegula with a blunt angle posteriorly (outline and arrow, Fig. 100A) and usually sparsely punctate medially (IS = 1–3 PD) ..................................................................... L. diabolicum sp. nov. [in part]
– Tegula with at least a small rounded posterior projection (outline and arrow, Fig. 100B) and usually densely punctate medially (IS ≤ 1 PD) .................................... L. stictaspis species complex [in part]
25. Mesoscutum finely and densely punctate (4–5 punctures present between posterior end of parapsidal line and lateral edge of mesoscutum, separated by <0.5 PD) (as in Fig. 93A); T3 usually with sparse tomentum throughout disc .................................................... L. helianthi (Cockerell, 1916) [in part]
– Mesoscutum coarsely punctate (2–3 punctures present between posterior end of parapsidal line and lateral edge of mesoscutum, which may be separated by up to 1 PD) (as in Fig. 93B); T3 with tomentum limited to basal band and, at most, a thin, sparse subapical band which is broadly interrupted medially .......................................................................................................................................... 26
26. T1 anterior slope shiny, mirror-smooth, with at most weak microsculpture not dulling surface (as in Fig.92B); scutellum often sparsely punctate in comparison to mesoscutum posterior margin (IS = 1–2PD) (Fig. 94A); metapostnotum rugae usually not reaching posterior margin or extending onto propodeum dorsolateral slope except at extreme base (Fig. 94A) .......... L. gaudiale (Sandhouse, 1924) [in part]
– T1 anterior slope dulled by coriarious microsculpture (as in Fig. 92A); scutellum densely punctate (IS <1 PD), similar to mesoscutum posterior margin (Fig. 94B); metapostnotum rugae reaching posterior margin and extending onto most of propodeum dorsolateral slope (Fig. 94B) ................... .............................................................................................................................. L. eremum sp. nov.
27. T2–3 with dense basal bands of tomentum obscuring the surface underneath and about as wide medially as laterally (Fig. 97B) (west of Rocky Mountains, except Hawaii) .................................... ........................................................................................................... L. diabolicum sp. nov. [in part]
– T2–3 with sparse basal bands of tomentum not obscuring the surface underneath and much narrower medially than laterally (as in Fig. 97A) (east of Rocky Mountains and Hawaii) ........................... 28
28. Face slightly longer on average (length/width ratio 0.81–0.87) (Fig. 101A); tegula slightly more sparsely punctate medially (IS = 1–2 PD); head and mesosoma usually blue to blue-green (southeastern United States and Hawaii) ..................................................................... L. puteulanum Gibbs, 2009
– Fact slightly shorter on average (length/width ratio 0.8–0.85) (Fig. 101B); tegula slightly more densely punctate medially (IS ≤ 1 PD); head and mesosoma usually olive green (eastern United States) ............................................................................................................................................. 29
29. Inner hind tibial spur with 3 or 4 subapical teeth ............................... L. tegulare (Robertson, 1890)
– Inner hind tibial spur with 2 subapical teeth ........................................ L. carlinvillense Gibbs, 2009
Key to males
1. Tegula impunctate except on extreme anterior margin (as in Fig. 81A); face uniformly covered in dense tomentum at least below eye emargination (Fig. 102B–D) .................................................... 2
– Tegula with at least a few distinct punctures medially, usually many (as in Fig. 81B–C), or (rarely) if impunctate, then face with dense tomentum limited to paraocular area (Fig. 102A) ................... 4
2. Mesoscutum tessellate anteriorly and often posteriorly; face with dense appressed tomentum at level of eye emargination and below (as in Fig. 102B) (eastern Texas, Nuevo Leon, and Tamaulipas) ..... ...................................................................................................................... L. rufodeludens sp. nov.
– Mesoscutum shiny, at most weakly tessellate anteromedially; face with dense appressed tomentum slightly above level of eye emargination (Fig. 102C) (Chihuahuan and Sonoran deserts) .............. 3
3. Tegula yellow-orange (Chihuahuan and Sonoran deserts) ................................. L. deludens sp. nov.
– Tegula dark brown (Chihuahuan desert) ......................................................... L. profundum sp. nov.
4. Face covered in dense appressed tomentum up to median ocellus or nearly so (Fig. 102D); mesoscutum often fringed with tomentum (as in Fig. 83A) .................................................................................. 5
– Face covered in dense appressed tomentum only up to eye emargination (Fig. 102B) or tomentum restricted to lower paraocular area (Fig. 102A); mesoscutum without tomentum (as in Fig. 83B) ... ........................................................................................................................................................... 7
5. Preëpisternum and metepisternum with sparse tomentum not obscuring the surface underneath(Fig.103A); face usually narrower (length/width ratio>0.83) (Fig. 104A) ......... L. gaudiale (Sandhouse, 1924)
– Preëpisternum and metepisternum with dense tomentum largely obscuring the surface underneath (Fig. 103B); face broad (length/width ratio ≤0.83) (Fig. 104B) ...................................................... 6
6. Mesoscutum mostly densely punctate (IS <1 PD); tegula inner posterior margin strongly concave and rugulose; metapostnotum rugae usually reaching posterior margin; head and mesosoma integument mostly olive green (north of ~34°) (Fig. 105A) ............................................... L. gloriosum sp. nov.
– Mesoscutum mostly moderately sparsely punctate (IS = 1–2 PD); tegula inner posterior margin weakly concave and distinctly punctate; metapostnotum rugae usually not reaching posterior margin; head and mesosoma integument mostly blue (south of ~34°) (Fig. 105B) ................ L. indagator sp. nov.
7. T1–T4 each strongly convex in lateral view (Fig. 106A); apical rim abruptly depressed and impunctate, contrasting with densely punctate discs along premarginal line (IS <1 PD) (Fig. 107A) .................. .................................................................................................................. L. coactus (Cresson, 1872)
– T1–T4 each mostly flat in lateral view (Fig. 106B); apical rim slightly depressed, with more gradual change or no change in sculpture across premarginal line (Fig. 107B) ............................................ 8
8. Tegula inner posterior margin deeply concave, with a broadly rounded posterior projection about the size of 0.5–1 lateral OD directed toward axilla and sometimes partially covering it; tegula relatively large (reaching or exceeding posterior margin of mesoscutum in dorsal view) and densely punctate throughout (IS <1 PD) (as in Fig. 87A) ........................................................................................... 9
– Tegula inner posterior margin weakly concave or straight, with a blunt posterior angle or point narrower than 0.5 lateral OD and not reaching axilla; tegula relatively small (at most reaching posterior margin of mesoscutum in dorsal view) and often more sparsely punctate medially (IS ≥ 1 PD) (as in Fig. 87B) ......................................................................................................................................... 17
9. Mesoscutum entirely densely punctate (IS <1 PD; sometimes with a few scattered IS = 1 PD submedially) (Fig. 108A) (Cascadia bioregion, California, and Hawaii) ....................................... 10
– Mesoscutum more sparsely punctate (most IS ≥1 PD) (Fig. 108B) (not occurring in Cascadia bioregion or Hawaii) ....................................................................................................................................... 12
10. T1 disc punctures slightly but distinctly sparser medially (IS = 1–3 PD) than those of T2 (IS = 1–2 PD); T1–T2 apical rims impunctate except for a few scattered punctures below T1 subapicolateral boss (Fig. 109A) ......................................................................... L. tegulariforme (Crawford, 1907)
– T1–T2 discs nearly identically, moderately densely punctate (IS = 1–2 PD) and with distinct punctures extending across premarginal line onto basal margin of apical rims (Fig. 109B) ...........................11
11. Tegula slightly smaller (maximum length usually ≤ 55% ITS and reaching but not clearly exceeding mesoscutum posterior margin in dorsal view) and with narrower posterior projection closer to the size of 0.5 lateral OD (Fig. 110A) ........................................ L. helianthi (Cockerell, 1916) [in part]
– Tegula slightly larger (maximum length>55% ITS and exceeding mesoscutum posterior margin in dorsal view) and with larger posterior projection closer to the size of 1 lateral OD (Fig. 110B) ....... ............................................................................................................ L. angelicum sp. nov. [in part]
12. T1–T2 apical rims with distinct punctures extending across premarginal line onto basal margin of apical rims (Fig. 109B) ................................................................................................................... 13
– T1–T2 apical rims impunctate (except sometimes with a few scattered, minute punctures below T1 subapicolateral boss) (as in Fig. 109A) .......................................................................................... 15
13. Face slightly longer (length/width ratio usually>0.86) (Fig. 111A); discs of T2–T3 and usually T1 with punctures very dense medially (IS <1 PD), often nearly touching (Fig. 112A) ........................ ................................................................................................... L. pseudotegulare (Cockerell, 1896)
– Face slightly shorter (length/width ratio ≤ 0.86) (Fig. 111B); discs of T1–T3 with punctures sparser medially (IS ≥1 PD), not close to touching (Fig. 112B) ................................................................ 14
14. Mesepisternum ventral half densely punctate (IS <1 PD); T1 shiny; tarsi and femur-tibia joints dark brown (southern California coast and Los Angeles basin) ................ L. angelicum sp. nov. [in part]
– Mesepisternum ventral half more sparsely punctate (IS ≥ 1 PD), T1 coriarious at base, tarsi and femurtibia joints orange, or occurring in Sonoran Desert and eastward (some specimens are morphologically indistinguishable and can only be separated by geography) .............................................................. ................................................................................................. L. stictaspis species complex [in part]
15. Tegula extremely large (maximum length>67% ITS and exceeding mesoscutum posterior margin by nearly 1 OD) (Fig. 113A); face slightly longer (length/width ratio usually>0.86) (as in Fig. 111A) (Neotropical Mexico, rarely occurring north to United States border) ......... L. magnitegula sp. nov.
– Tegula smaller (maximum length ≤ 67% ITS and exceeding mesoscutum posterior margin by less than 1 OD if at all) (Fig. 113B); face slightly shorter (length/width ratio usually <0.86) (Fig. 111B) ..... ......................................................................................................................................................... 16
16. Metapostnotum shiny with strong subparallel rugae (as in Fig. 114A) (east of Rocky Mountains to Atlantic coast) ........................................................................ L. ellisiae (Sandhouse, 1924) [in part]
– Metapostnotum dulled by strong microsculpture or, if shiny, then rugae anastomosing (Fig. 114B) (west of Rocky Mountains and east to ~102°) ........................ L. stictaspis species complex [in part]
17. Face with tomentum limited to lower paraocular area and clypeus without tomentum ................. 18
– Face with uniformly dense tomentum below eye emargination, or if denser in lower paraocular area, then clypeus with some sparse tomentum ...................................................................................... 19
18. Tegula dark brown with deep, crowded punctures (IS = 0 PD) (high elevations of southwestern United States) .................................................................................................................. L. eremum sp. nov.
– Tegula yellow-orange and very finely and sparsely punctate medially (IS = 2–6 PD) (Florida and Bahamas) .............................................................................................. L. surianae (Mitchell, 1960)
19. T1–T3 apical rims with distinct punctures extending across premarginal line, at least onto basal margin of T1–T2 apical rims (Fig. 109B) ................................................................................................... 20
– T1–T3 apical rims impunctate (except sometimes with a few scattered, minute punctures below T1 subapicolateral boss) (as in Fig. 109A) .......................................................................................... 22
20. Tegula inner posterior margin concave, with a distinct posterior projection longer than 1 mesoscutum PD, and usually densely punctate medially (IS ≤ 1 PD) (Fig. 115A); clypeus usually with tomentum about as dense as on lower paraocular area (as in Fig. 102B) (Cascadia bioregion, Hawaii, and California) ........................................................ L. helianthi (Cockerell, 1916) [in part]
– Tegula inner posterior margin straight or weakly concave, with at most a small posterior bump about 1 mesoscutum PD long, and usually sparsely punctate medially (IS>1 PD) (Fig. 115B); clypeus usually with tomentum sparser than on lower paraocular area (Fig. 102A) (not occurring in Cascadia bioregion or Hawaii) ....................................................................................................................... 21
21. T1–T2 apical rims punctate except T1 apicomedially and far sides of T2 (Fig. 116A); T3 apical rim with at least some punctures; metapostnotum shiny (including posterior margin) ............................ ......................................................................................................................... L. holzenthali sp. nov.
– T1–T2 apical rims punctate only on basal margins (Fig. 116B); T3 apical rim impunctate; metapostnotum dulled by strong imbricate microsculpture (most noticeable on posterior margin) .. .................................................................................................... L. perparvum (Ellis, 1914) [in part]
22. Mesoscutum with sparse erect setae up to 1 OD long, with several gaps half a seta’s length wide or wider in lateral view, these setae appearing thin and simple at 40 × magnification (as in Fig. 78A– B) ............................................................................................... L. perparvum (Ellis, 1914) [in part]
– Mesoscutum with dense erect setae 1 OD long or slightly longer, with no gaps half a seta’s length wide in lateral view, these setae distinctly plumose at 40 × magnification (as in Fig. 78C–D) ......... ......................................................................................................................................................... 23
23. Discs of T2–T3 uniformly punctate, with dense punctures along premarginal line (IS ≤1 PD), sharply contrasting with impunctate apical rims (Fig. 117A) ..................................................................... 24
– Discs of T2–T3 becoming slightly more sparsely punctate near and on premarginal line, without a sharp contrast between discs and apical rims (Fig. 117B) .............................................................. 25
24. Face slightly longer (length/ width ratio ≥ 0.86) (Fig. 118A); tegula slightly more sparsely punctate medially (IS = 1–2 PD); head and mesosoma blue (Hawaii and southeastern United States) .................................................................................................... L. puteulanum Gibbs, 2009
– Face slightly shorter (length/width ratio usually <0.86) (Fig. 118B); tegula relatively densely punctate medially (IS ≤1 PD); head and mesosoma green to bluish (widespread across eastern Canada and United States, excluding Florida) ....................................................... L. tegulare (Robertson, 1890) [L.carlinvillense (Gibbs, 2009) may also key here, but male diagnostic characters are not currently known. Small specimens from Illinois toAlabama should be identified with caution,ideally with associated females.]
25. Preëpisternum and hypoepimeral area very finely punctate to areolate with punctures smaller than on mesepisternum (Fig. 119A) (Florida) ............................................... L. lepidii (Graenicher, 1927)
– Preëpisternum and hypoepimeral area more coarsely punctate to areolate with punctures about the same size as on mesepisternum (Fig. 119B) (not occurring in Florida) ......................................... 26
26. Mesoscutum punctures between parapsidal lines all separated by1PD or slightly more or less(Fig.120A); metapostnotum usually shiny (east of Rocky Mountains) ..... L. ellisiae (Sandhouse, 1924) [in part]
– Mesoscutum between parapsidal lines more irregularly and sparsely punctate, with some IS <1 PD and some IS ≥ 2 PD (Fig. 120B); metapostnotum usually dulled by strong imbricate microsculpture (west of Rocky Mountains and east to ~102°) ................................................................................ 27
27. Tegula relatively small, usually not reaching mesoscutum posterior margin in dorsal view, and inner posterior margin straight or weakly concave, with at most a small posterior bump about 1 mesoscutum PD long (as in Fig. 100A) .......................................................... L. diabolicum sp. nov.
– Tegula relatively large, usually reaching mesoscutum posterior margin in dorsal view, and inner posterior margin concave, with a distinct posterior projection longer than 1 mesoscutum PD (as in Fig. 100B) ............................................................................... L. stictaspis species complex [in part]
description: Published as part of Gardner, Joel & Gibbs, Jason, 2023, Revision of the Nearctic species of the Lasioglossum (Dialictus) gemmatum species complex (Hymenoptera: Halictidae), pp. 1-222 in European Journal of Taxonomy 858 (1) on pages 190-216, DOI: 10.5852/ejt.2023.858.2041, http://zenodo.org/record/7629347