1	Base of marginal cell broad, basal angle (within marginal cell between pterostigmal margin and r-rs) slightly acute (not under 68°) to orthogonal; marginal cell, at apex of pterostigma, broader than submarginal cell area; forewing less, usually much less, than 4 mm long [genus Trigonisca Moure, s.l.]	2
–	Base of marginal cell comparatively narrow, basal angle strongly acute (≤ 50°) (except ~ 80° in Nogueirapis Moure); marginal cell, at apex of pterostigma, little if any broader than submarginal cell area; forewing usually > 4 mm long	5
2(1)	Integument of mesoscutum and mesoscutellum smooth and shiny; preoccipital carina absent; transscutal sulcus between axillae shallowly impressed; mesoscutellum comparatively flat and low, acutely rounded apically in profile and slightly raised above level of metanotum	3
–	Integument of mesoscutum and mesoscutellum matte, microalveolate to tessellate; preoccipital carina present at least laterally, sometimes weakly so; transscutal sulcus between axillae deeply and broadly impressed; mesoscutellum gently convex, broadly rounded apically in profile and distinctly raised above level of metanotum	4
3(2)	Malar space as long as 2× flagellar diameter; retrodorsal margin of metatibia gently arched, without projection at superior distal angle; superior parapenicillum curved but not greatly sinuate; head width ≥ 1.0 mm	Trigonisca (Leurotrigona) Moure
–	Malar space as long as flagellar diameter; retrodorsal margin of metatibia somewhat sinuous, with superior distal angle projected; superior parapenicillum markedly sinuate; head width < 1.0 mm	Trigonisca (Exochotrigona) Engel
4(2)	Labrum simple; setae along retrodorsal margin of metatibia as long as or shorter than maximum metatibial width	Trigonisca (Trigonisca) Moure
–	Labrum bituberculate; setae along retrodorsal margin of metatibia distinctly longer than maximum metatibial width	Trigonisca (Celetrigona) Moure
5(1)	Retrolateral surface of metatibia with strongly depressed, shiny, superior marginal subglabrate zone, which at least apically is usually approximately as broad as longitudinal median keirotrichiate ridge, and midway of metatibial length is at least half as wide as keirotrichiate ridge	6
–	Retrolateral surface of metatibia with depressed superior marginal subglabrate zone narrower (much less than half as wide as area with keirotrichia) or absent, keirotrichia extending to or close to margin	24
6(5)	Compound eyes with inconspicuous setae; rastellum strongly developed	7
–	Compound eyes setose; rastellum reduced to tapering setae	Trichotrigona Camargo & Moure
7(6)	Face of ordinary shape, minimum distance between compound eyes little more than to less than length of compound eye; clypeus usually > 2× as broad as long; malar space slightly > 1.5× as long as flagellar diameter or usually much less; keirotrichiate zone on retrolateral surface of worker metatibia usually narrow, rarely > 1.5× as wide as depressed superior marginal subglabrate zone at midlength of metatibia	8
–	Face short and broad, minimum distance between compound eyes much greater than length of compound eye; clypeus < 2× as broad as long; malar space almost 2× as long as flagellar diameter; keirotrichiate zone on retrolateral surface of worker metatibia nearly twice as wide as depressed superior marginal subglabrate zone at midlength of metatibia	Oxytrigona Cockerell
8(7)	Preoccipital carina absent; lower face and genal area finely sculptured like upper part of head and mesoscutum	9
–	Preoccipital carina strong and shiny across full width behind vertex; lower face and genal area shiny and coarsely punctate in contrast to dull, densely, minutely punctate upper face, genal area, and mesoscutum	Cephalotrigona Schwarz
9(8)	Mandible of worker with 4 or 5 teeth along distal margin; retrolateral surface of metabasitarsus of males and workers with basal sericeous area [genus Trigona Jurine, s.l.]	10
–	Mandible of worker with lower half or 2/3 of distal margin edentate, upper part of margin with 1 or usually 2 teeth; retrolateral surface of metabasitarsus of males without basal sericeous area, that of workers, variable	17
10(9)	Mandible with 4 teeth	11
–	Mandible with 5 teeth	12
11(10)	Labrum simple, surface gently and evenly convex; wings dichroic, proximally infuscate, apically whitish; pterostigma yellowish brown; scape black	Trigona (Aphaneuropsis) Engel
–	Labrum bigibbous, with pronounced mediolongitudinal furrow; wings uniformly fuscous; pterostigma brown to dark brown; scape paler ventrally, pale brown to yellowish brown	Trigona (Koilotrigona) Engel
12(10)	Metatibia with distinct corbicula on apical prolateral surface (corbicular surface concave), superior distal angle present, retromarginal fringe setae abundant	13
–	Metatibia without defined corbicula on apical prolateral surface (corbicular surface not concave), superior distal margin rounded, retromarginal fringe setae less numerous	Trigona (Necrotrigona) Engel
13(12)	Labrum simple, surface gently and evenly convex; vertex with distinct postocellar ridge; integument entirely dark brown to black (except entirely orange in Trigonadallatorreana Friese)	14
–	Labrum bigibbous, with mediolongitudinal furrow (furrow somewhat weak in T.williana Friese); vertex without postocellar ridge, or ridge quite weak; integument largely yellowish orange (head, mesoscutum, and parts of pleura sometimes largely black but clypeus and antenna always yellowish to yellowish orange)	Trigona (Aphaneura) Gray
14(13)	Wing membrane not as below, if slightly paler apically, then transition gradual across wing length; metatibial width variable, sometimes comparatively narrow	15
–	Wing membrane strikingly dichroic, proximally darkly infuscate, apically whitish; metatibia broad apically, with broadly rounded retromarginal contour	Trigona (Dichrotrigona) Engel
15(14)	Small bees, head width ≤ 2.5 mm; forewing (including tegula) length < 6.5 mm; metatibia narrow, retromarginal contour comparatively straight until apical fifth	16
–	Larger bees, head width typically ≥ 2.5 mm or greater, rarely as small as 2.45 mm (in some T.corvina Cockerell), forewing (including tegula) length ≥ 6.9 mm; metatibia broader, typically with broadly rounded retromarginal contour	Trigona (Trigona) Jurine
16(15)	Apical fundal surface of metatibia near corbicula with abundant minute, fine, appressed setae; scape with prominent, thick, black, bristle-like setae along length, such setae often as long as scape diameter; clypeus in profile with numerous, erect, black, bristle-like setae; distance from median ocellus to postocellar ridge about ocellar diameter; smaller bees, intertegular distance ≤ 1.35 mm	Trigona (Nostotrigona) Engel
–	Apical fundal surface of metatibia near corbicula with minute, fine, appressed setae either lacking or exceedingly sparse; scape without thick bristle-like setae, with fine, paler setae, such setae shorter than scape diameter; clypeus in profile with a few short, fine setae, without black bristle-like setae; distance from median ocellus to postocellar ridge less than ocellar diameter; larger bees, interegular distance ≥ 1.4 mm	Trigona (Ktinotrofia) Engel
17(9)	Retrolateral surface of metabasitarsus of worker without basal sericeous area, rather uniformly setose	18
–	Retrolateral surface of metabasitarsus of worker with basal sericeous area covered with minute setae or sometimes lacking setae	Tetragonisca Moure
18(17)	Mesotibial spur absent; gena with sparse setation, not obscuring integument; mandibular teeth small denticles; profundal surface with setation variable, typically with numerous plumose setae amid simple, erect, setae; M+Cu in line with 1Cuα and 1Cuβ, or, if 1Cuα more transverse, then 1Cuβ offset from M+Cu by vein width	19
–	Mesotibial spur present; gena with dense setation, with overall velvety appearance; mandibular teeth typically strong and prominent; profundal surface with sparse plumose setae amid simple, erect, setae; M+Cu distinctly offset from 1Cuβ, with 1Cuα nearly transverse and 1Cuβ offset by more than vein width and superficially appearing as if arising from 1cu-a	22
19(18)	Metasoma short, about as wide as mesosoma, dorsoventrally flattened; retrodorsal margin of metatibia of worker usually with few plumose setae, of those, most with only 2–6 scattered branches not concentrated toward apices; yellow markings absent, integument brown to black; vein M of forewing dark almost to wing margin; discs of metasomal sterna with abundant, erect setae, some with curved apices [genus Geotrigona Moure, s.l.]	20
–	Metasoma usually narrower than mesosoma, often noticeably elongate; retrodorsal margin of metatibia of worker with numerous plumose setae, typically with abundant branches toward apices; yellow markings always present, albeit sometimes reduced and restricted to clypeus and paraocular areas; vein M of forewing usually fading away near widest part of wing; discs of metasomal sterna with diffusely scattered, long, erect, simple setae	21
20(19)	Metatibia with apical margin rounding continuously to broadly rounded superior distal curve, not projected into a distinct angle or tooth before superior angle; apical margin straight or weakly concave	Geotrigona (Geotrigona) Moure
–	Metatibia with apical margin distinctly projecting into an angle or tooth before superior angle; apical margin, between apex of tooth and penicillum, deeply concave	Geotrigona (Chthonotrigona) Engel
21(19)	Posterior margin of vertex not elevated; superior distal angle of metatibia of worker broadly rounded; labial palpus with numerous elongate, sinuous setae (setae of first two palpomeres as long as palpomere I and longer than palpomere II, typically > 2× palpal width); smaller bees, typically ≤ 7 mm in length	Frieseomelitta Ihering
–	Posterior margin of vertex elevated as strong, setose ridge between summits of compound eyes; superior distal angle of metatibia of worker acute; labial palpus with some long setae (setae ≤ 1.5× palpal width) on first two palpomeres, such setae apically curved or rarely sinuous; larger bees, ~ 8–9 mm in length	Duckeola Moure
22(18)	Basal area of propodeum setose, sometimes with mediolongitudinal glabrous line between lateral areas of wispy setae [genus Ptilotrigona Moure, s.l.]	23
–	Basal area of propodeum wholly glabrous	Tetragona Lepeletier & Audinet-Serville
23(22)	Basal area of propodeum pubescent; labial palpus with setae no longer than palpal width and straight or nearly so	Ptilotrigona (Ptilotrigona) Moure
–	Basal area of propodeum with mediolongitudinal glabrous line between lateral areas of wispy setae; labial palpus with long, sinuous setae	Ptilotrigona (Camargoia) Moure
24(5)	Prolateral surface of metatibia convex, without corbicula, proventral margin convex like retromarginal contour; penicillum absent; rastellum consisting of tapering setae; first flagellomere of worker nearly as long as combined lengths of second and third flagellomeres, that of male nearly as long as second flagellomere [genus Lestrimelitta Friese, s.l.]	25
–	Prolateral surface of metatibia flat or concave at least apically, forming corbicula, proventral margin gently convex to concave, differing from largely or wholly convex retromarginal contour; penicillum present; rastellum variable; first flagellomere of worker shorter than combined lengths of second and third flagellomeres, that of male much shorter than second flagellomere	27
25(24)	Propodeal spiracle ovoid	26
–	Propodeal spiracle elongate linear, slit-like	Lestrimelitta (Hyrolestris) Engel
26(25)	Propodeal spiracle with upper margin pronounced relative to lower margin; inner orbits of compound eyes parallel to faintly diverging; larger bees, total length > 5 mm	Lestrimelitta (Lestrimelitta) Friese
–	Propodeal spiracle with upper margin similar to lower margin; inner orbits of compound eyes weakly converging below; small bees, total length < 5 mm	Lestrimelitta (Apiraptor) Engel
27(24)	Hind wing with 9–14 (rarely 8) hamuli; wings extending little if any beyond apex of metasoma; pterostigma with margin within marginal cell straight or weakly concave (body apiform; basal area of propodeum dull, setose) [genus Melipona Illiger, s.l.]	28
–	Hind wing with 5–7 hamuli, rarely up to 9 or even 10; wings long, extending well beyond apex of metasoma; pterostigma with margin within marginal cell slightly convex	33
28(27)	Vertex posterior to ocelli at most only slightly elevated; ocellocular area comparatively flat, not depressed; pronotal posterior dorsal ridge typically present and forming a surface of smooth and rounded contour bordering mesoscutum, rarely forming a crest; lower surface of mesepisternum variable, often microreticulate and matte; mesoscutum, axilla, and mesoscutellum often with yellow maculation	29
–	Vertex posterior to ocelli distinctly elevated; ocellocular area depressed, forming a distinct concave surface; pronotal posterior dorsal ridge virtually absent, pronotal posterior border tightly approximating anterior border of mesoscutum and forming a sharp crest; ventral surface of mesepisternum shiny; mesoscutum, axilla, and mesoscutellum without yellow maculation	Melipona (Melipona) Illiger
29(28)	Mandible with comparatively small preapical teeth, separation between first (P1) and second (P2) preapical teeth a smooth arc; anterolateral areas of mesoscutum with setae similar in color to those of remainder of mesoscutum; superior apical angle of metatibial apical margin forming a short projection	30
–	Mandible with comparatively more prominent preapical teeth, separation between first (P1) and second (P2) preapical teeth a deep V-shaped incision; anterolateral areas of mesoscutum with dense tufts of testaceous or tawny setae contrasting with setae of remainder of mesoscutum; superior apical angle of metatibial apical margin forming a prominent projection	Melipona (Melikerria) Moure
30(29)	Malar space short, distinctly shorter than flagellar diameter; upper interorbital distance distinctly less than length of compound eye; interocellar distance greater than ocellocular distance	31
–	Malar space long, as long as or longer than flagellar diameter; upper interorbital distance equal to or slightly less than length of compound eye; interocellar distance typically shorter than ocellocular distance	32
31(30)	Mesoscutellum with prominent, broad yellow maculation along lateral margins, yellow maculation extending from axilla along nearly entire margin of equal width, extending anterior to tegula and nearly to pronotal lobe; clypeus slightly arched	Melipona (Meliponiella) Melo
–	Mesoscutellum without yellow lateral borders or, if some yellow maculation present, then broader near axilla and tapering anteriorly before disappearing entirely by middle of tegula; clypeus flat	Melipona (Eomelipona) Moure
32(30)	Lower half of face polished and shiny, devoid, or nearly so, of setae, contrasting with upper half of face; body length typically ≥ 12 mm	Melipona (Mouremelia) Engel
–	Lower half of face dull, matte, with numerous setae, and without contrasting setation between lower and upper halves of face; body length typically ≤ 11 mm	Melipona (Michmelia) Moure
33(27)	Anterior margin of mesoscutellum with shiny, longitudinal, V- or U-shaped median depression opening anteriorly into mesoscutal-mesoscutellar fossa; preoccipital carina present, extending far down each side of head	34
–	Anterior margin of mesoscutellum without shiny, longitudinal, median depression; preoccipital carina absent or weakly indicated only by transverse dorsal section posterior to vertex (except in Paratrigonoides Camargo & Roubik)	42
34(33)	Integument of head and mesosoma, or at least mesoscutellum, with coarse, cribriform punctation; posterior margin of mesoscutellum notched or emarginate medially; anterior margin of pronotal lobe with strong, transverse carina [genus Nannotrigona Cockerell, s.l.]	35
–	Integument of head and mesosoma with fine punctation; posterior margin of mesoscutellum entire; anterior margin of pronotal lobe rounded [genus Scaptotrigona Moure, s.l.]	36
35(34)	Mesoscutum and mesoscutellum with dense, coarse, cribriform punctures; larger bees, head width > 1.6 mm	Nannotrigona (Nannotrigona) Cockerell
–	Mesoscutum sparsely punctate, integument between punctures shiny, contrasting denser, coarser punctation of mesoscutellum; smaller bees, head width < 1.6 mm	Nannotrigona (Lispotrigona) Gonzalez & Engel
36(34)	Bristle-like setae of vertex, mesoscutum, and mesoscutellum long, distinctly longer than median ocellar diameter	37
–	Bristle-like setae of vertex, mesoscutum, and mesoscutellum short, distinctly shorter than median ocellar diameter	Scaptotrigona (Sakagamilla) Moure
37(36)	Scape and supraclypeal area without minute, erect to suberect, bristle-like setae, at most sometimes with 1 or 2 suberect setae at extreme base of scape, otherwise setation minute and appressed; tergal setation not as below; integumental coloration variable	38
–	Scape along its length and supraclypeal area with numerous, minute, erect to suberect, bristle-like setae; all metasomal terga with dense, long, fine, erect, simple, yellow setae intermixed with similar short, appressed to decumbent setae; integument wholly yellow orange to orange	Scaptotrigona (Dasytrigona) Engel
38(37)	Discs of metasomal terga III–V with abundant, prominent, erect to subdecumbent, bristle-like setae, such setae frequently, but not universally, arising amid dense tomentum	39
–	Discs of metasomal terga III–V without bristle-like setae, instead with only fine, short to minute setae, such setae typically appressed to decumbent, if bristle-like setae present, then short (< 1/2 ocellar diameter) and confined to lateral margins or rarely sparse over disc and not associated with tomentum	41
39(38)	Metasomal terga III–V not covered in yellow tomentum, at most with diffuse areas of whitish or yellowish tomentum laterally on discs of terga IV–VI [care should be taken as sometimes the tomentum is difficult to see or may be largely rubbed off and only present in small lateral areas or under the margin of the preceding tergum]	40
–	Metasomal terga III–V covered with dense, yellow, plumose tomentum, typically obscuring integument [except in Scaptotrigonafaviziae Engel tomentum interrupted broadly medially, and largely absent on tergum III]	Scaptotrigona (Scaptotrigona) Moure
40(39)	Face below tangent of antennal toruli with a large yellow to yellowish brown patch, clypeus not concolorous with frons; upper frons with minute punctures well spaced, separated by 1–2× a puncture width	Scaptotrigona (Baryorygma) Engel
–	Face below tangent of antennal toruli brown to dark brown, largely concolorous with remainder of head, clypeus brown or concolorous with frons; upper frons with minute punctures dense, separated by much less than puncture width, nearly contiguous in places	Scaptotrigona (Eoscaptotrigona) Engel
41(38)	Metasomal terga III–V finely imbricate, somewhat shiny, with scattered punctures; mesoscutellum short, broadly rounded apically, apex extending only to basal margin of propodeum, not or barely overhanging propodeum	Scaptotrigona (Astegotrigona) Engel
–	Metasomal terga III–V coarsely imbricate to densely punctate; mesoscutellum long, apex somewhat blunt medio-apically, apex extending well past basal margin of propodeum and overhanging propodeum	Scaptotrigona (Gymnotrigona) Engel
42(33)	Mandible of worker with four apical teeth (lower two sometimes united by translucent septum but teeth still recognizable); mesoscutellum, as seen in lateral view projecting posteriorly as thin shelf over median part of metanotum [genus Paratrigona Schwarz, s.l.]	43
–	Mandible of worker with (rarely without) 1 or 2 denticles at upper end of apical margin, otherwise without teeth; mesoscutellum, as seen in lateral view, rather thick and rounded, not projecting as thin shelf over metanotum	44
43(42)	Metasomal terga shiny, in stark contrast with dull imbricate or coriaceous integument of head and mesosoma; setae quite conspicuous	Paratrigona (Aparatrigona) Moure
–	Metasomal terga dull imbricate or coriaceous, as on head and mesosoma; head, mesosoma, and terga typically with only exceedingly short and inconspicuous setae, rarely with more distinctly erect setae	Paratrigona (Paratrigona) Schwarz
44(42)	Metatibia of worker greatly broadened, spoon-shaped, ~ 3× as wide as metafemur, prolateral surface largely occupied by corbicula, proventral margin of metatibia with distal one-half convex; basal area of propodeum densely setose [genus Partamona Schwarz, s.l.]	45
–	Metatibia of worker not greatly broadened, < 3× as wide as metafemur, corbicula extending but little if at all basad middle of metatibia, proventral margin of metatibia convex only in distal 1/4 or less; basal area of propodeum usually asetose	46
45(44)	Cuticle of mesosoma shiny with minute, widely separated punctures; yellow of face pale and inconspicuous; metasomal terga without yellow maculations; worker gonostylus a rounded tubercle with few setae	Partamona (Partamona) Schwarz
–	Cuticle of mesosoma dull and minutely roughened; paraocular areas largely bright yellow; metasomal terga usually with yellow bands or lateral spots; worker gonostylus ~ 1.5× as long as broad, and setose	Partamona (Parapartamona) Schwarz
46(44)	Malar space much < 1/5 as long as compound eye; retrodorsal margin of metabasitarsus gently convex; yellow markings almost always present, at least on face	47
–	Malar space ~ 1/5 as long as compound eye; retrodorsal margin of metabasitarsus strongly convex medially; yellow markings absent	Meliwillea Roubik, Lobo Segura, & Camargo
47(46)	Superior margin of retrolateral surface of metatibia not depressed, although shiny and in contrast to keirotrichiate area; concave surface of corbicula occupying full width of distal 1/2 of metatibia	48
–	Superior margin of retrolateral surface of metatibia strongly depressed, shiny, in sharp contrast to keirotrichiate area [except not depressed in apical 1/3 of metatibia of Scaura (Schwarzula)]; concave surface of corbicula usually not occupying whole distal 1/2 of metatibia	49
48(47)	Integument of head and mesosoma dull, microreticulate; preoccipital carina lamellate across upper part of head, with row of coarse setae, branched apically; supraclypeal area expanded laterally, forming flange partly covering antennal torulus; long setae lacking centrally on corbicular surface	Paratrigonoides Camargo & Roubik
–	Integument largely shiny; preoccipital carina absent, without row of course setae; supraclypeal area not expanded laterally; 2 or 3 long setae present centrally on corbicular surface	Nogueirapis Moure
49(47)	Metabasitarsus thickened, prolateral surface swollen, nearly as broad as or broader than metatibia, setae of inferior retrolateral margin curved apically; yellow maculation absent; rastellum nearly occupying full length of metatibial apical margin [genus Scaura Schwarz, s.l.]	50
–	Metabasitarsus not thickened, prolateral surface flat, much narrower than metatibia; setae of inferior retrolateral margin straight; yellow maculation present; rastellum occupying two-thirds or less of metatibial apical margin	52
50(49)	Metabasitarsus as wide as or wider than metatibia; malar space shorter than flagellar diameter; gena in profile narrower than compound eye; mandible virtually edentate	51
–	Metabasitarsus narrower than metatibia; malar space as long as flagellar diameter; gena in profile broader than compound eye; mandible with two denticles	Scaura (Schwarzula) Moure
51(50)	Metasoma elongate, length ≥ 3× width; metasomal tergum VI with dark fuscous or black setae	Scaura (Scaura) Schwarz
–	Metasoma subtriangular, length 1.5× width; metasomal tergum VI with white setae	Scaura (Scauracea) Engel
52(49)	Head and mesosoma largely smooth and shiny between scattered small setiferous punctures, rarely granulose-microrugulose and more matte; mesepisternum with at least some simple erect setae among plumose setae	53
–	Head and mesosoma with large, dense punctation or integument matte and microreticulate with indistinct punctures; mesepisternum with erect setae always plumose or minutely branched	55
53(52)	Mesoscutum shiny and smooth, punctures small to minute and distinctly separated, often widely so [genus Plebeia Schwarz, s.l.]	54
–	Mesoscutum generally matte owing to finely microrugulose-granulose sculpture resulting from dense, coarse, shallow punctures	Asperplebeia Engel
54(53)	Forewing 2Cu a faint nebulous trace, weakening apically and disappearing by wing margin; minute bees, 2–3.5 mm in length	Plebeia (Nanoplebeia) Engel
–	Forewing 2Cu terminating on wing margin as a dark brown to brown tubular vein or nebulous trace, no weaker at terminus than on remigium; small bees, typically ≥ 3.5 mm in length	Plebeia (Plebeia) Schwarz
55(52)	Head and mesosoma with conspicuous yellow maculation; erect sternal setae predominantly plumose; moderate-sized bees, body length > 5 mm	56
–	Head and mesosoma with exceptionally small areas of yellow maculation; erect sternal setae simple; smaller bees, body length < 4 mm	Friesella Moure
56(55)	Integument without metallic reflections; mesoscutum matte, integument microreticulate, with punctures indistinct [genus Schwarziana Moure, s.l.]	57
–	Integument with weak metallic reflections; mesoscutum shiny, punctures distinct and dense	Mourella Schwarz
57(56)	Malar space shorter than flagellar diameter; mesepisternal setae long, longer than protibial width, and dense, sometimes obscuring integument	Schwarziana (Schwarziana) Moure
–	Malar space as long as flagellar diameter; mesepisternal setae short, shorter than protibial width, and sparser	Schwarziana (Chapadapis) Engel