1	Forewing length < 3.5 mm; hind wing without closed cells, veins closing radial and cubital cells, if visible at all, clear and unpigmented; forewing with 2Rs, 1rs-m, and 2rs-m almost always completely absent, thus indications of submarginal cells absent; at least distal part of second cubital cell (= subdiscoidal cell) of forewing undefined or defined by completely unpigmented vein traces; vein 2M of forewing terminating without bend at about position of anterior end of 1m-cu (i.e., 3M absent), which, however, is absent or spectral (sensu Mason 1986; = barely discernible)	2
–	Forewing length ~ 4 mm or more; hind wing commonly with radial and cubital cells closed by at least weakly brownish nebulous veins; forewing with 2Rs and 1rs-m usually weakly indicated, first submarginal cell thus usually recognizable; second cubital cell of forewing completely indicated, at least by faint veins; vein M of forewing extending at least slightly beyond position of anterior end of 1m-cu and angulate at end of that crossvein (i.e., 3M distinct from 2M, with at least tubular to nebulous stub), which is usually at least faintly visible	4
2(1)	Distal part of prolateral surface of metatibia flat or concave, bordered by long setae, forming corbicula; penicillum present; clypeus twice as wide as long or less	3
–	Prolateral surface of metatibia convex, without corbicula; penicillum absent; clypeus much > 2× as wide as long	Liotrigona (Cleptotrigona) Moure
3(2)	Superior distal angle of metatibia forming distinct angle; mesoscutum and mesoscutellum smooth and shiny; gonostyli much longer than broad, flat, adjacent, or separated by less than one gonostylar width, without setae but with gonotrichia	Liotrigona (Liotrigona) Moure
–	Superior distal angle of metatibia a rounded contour; mesoscutum and mesoscutellum matte, micro-alveolate to imbricate; gonostyli minute, tuberculiform, separated by several gonostylar widths, with setae but without gonotrichia	Hypotrigona Moure
4(1)	Retrolateral surface of metatibia with depressed upper marginal glabrate area narrow (much < 1/2 as wide as broad area with keirotrichia) or absent, keirotrichia extending to or close to margin; first metasomal segment broader than long	5
–	Retrolateral surface of metatibia with strongly depressed, shiny, superior marginal glabrate area nearly as broad apically as longitudinal median keirotrichiate plateau, and ~ 1/2 as wide as keirotrichiate plateau midway of metatibial length; first metasomal segment longer than broad	Dactylurina Cockerell
5(4)	Metatibia rather spoon-shaped, superior distal angle rounded but with coarse, amber-colored to blackish setae (superior parapenicillum); sting stylet distinct, acute	6
–	Metatibia slender, triangular with distinct superior distal angle supporting long, pale setae (not especially coarse); sting stylet a mere rounded convexity	Plebeina Moure
6(5)	Propodeal profile with slanting dorsal portion rounding onto vertical portion; corbicula occupying more than distal half of metatibia; metasomal terga at least partly shiny [apical reflexed process of sternum VI of male longer than body of sternum]	7
–	Propodeal profile largely vertical; corbicula occupying less than distal half of metatibia; metasomal terga dull, minutely sculptured [apical reflexed process of sternum VI of male short and rounded]	Meliponula Cockerell
7(6)	Head and mesosoma without yellow markings; retrolateral surface of metatibia without well-defined, shiny, depressed superior margin, although keirotrichiate not reaching margin, at least distally [genus Axestotrigona Moure, s.l.]	8
–	Head and mesosoma with yellow markings; retrolateral surface of metatibia with shiny superior margin, at least slightly depressed	9
8(7)	Basal area of propodeum finely tessellate to microalveoate, sometimes faintly so and appearing nearly smooth, and laterally setose (sometimes lateral patches of setae sparse and wispy or difficult to discern in worn or dirty individuals, such as with considerable resin on body); wing membranes hyaline clear to lightly infuscate (parchment-colored) or ferruginous	Axestotrigona (Axestotrigona) Moure
–	Basal area of propodeum glabrous and smooth; wing membranes darkly infumate throughout	Axestotrigona (Atrichotrigona) Engel
9(7)	Basal area of propodeum pubescent [genus Meliplebeia Moure, s.l.]	10
–	Basal area of propodeum glabrous	Plebeiella Moure
10(9)	Mesoscutum tessellate; mandibular teeth small; scape as long as antennal-ocellar distance; basal vein (1M) slightly distad 1cu-a; superior parapenicillum well developed	Meliplebeia (Meliplebeia) Moure
–	Mesoscutum punctate; mandibular teeth strong; scape shorter than antennal-ocellar distance; basal vein (1M) slightly basad 1cu-a; superior parapenicillum scarcely definable	Meliplebeia (Apotrigona) Moure