Key to the species of Trimeria of Brazil

1 Gena flat, not excavated; lateral portion of occipital carina not raised into a translucent lamella and not reaching the base of mandible; eyes hairy; mid tibia with two apical spurs; angle between anterior and lateral portions of mesepisternum rounded, pleural carina absent; labrum distinctly narrower than apex of clypeus; clypeus nearly as wide as long (figs. 1, 2); punctures evident, but almost indistinct on head and very weak and shallow on metasomal terga. Male: apical flagellomere hooked; posterior margin of S2 with a strong and blunt medial protuberance; S8 distinctly convex in lateral view ................................................................................................................ T . robusta n. sp.

1’ Gena excavated; lateral portion of occipital carina strongly produced and reaching base of mandible, raised into a translucent lamella in females; eyes bare; mid tibia with one apical spur; angle between anterior and lateral portions of mesepisternum sharp, pleural carina well developed; labrum as wide as apex of clypeus; clypeus nearly one and a half times as wide as long; body punctures coarse, especially on metasomal terga. Male: apical flagellomere normal; S2 without any protuberance; S8 flat in lateral view.......................................................................................................... 2

2 Female: flat basal portion of scutellum more than twice as long as width of scutellar sulcus; dorsal depressions of scutellum with dense brownish pubescence; fore femur distinctly angulate near base. Male: mid coxa with a short tooth ventrally; posterior margin of S7 strongly depressed and concave medially ..... T . americana (de Saussure)

2’ Female: flat basal portion of scutellum short, less than one and a half times as long as width of scutellar sulcus; pubescence on dorsal depressions of scutellum sparse and not conspicuous; fore femur not angulate near base. Male: mid coxa without tooth; posterior margin of S7 flat and nearly straight [the male of T. rubra n. sp. is unknown] ....................................................................................................................................... 3

3 Head and mesosoma with abundant yellow marks, pronotum extensively reddish yellow dorsally (figs. 3, 9); shining area of female hind tibia large, its basal margin often reaching middle of tibia (fig. 12) .............................................................. T . rubra n. sp.

3’ Head and mesosoma mostly black, pronotum black except for a yellow stripe adjacent to dorsal pronotal carina; shining area of female hind tibia smaller, its basal margin not reaching middle of tibia .................................................................... T . howardi Bertoni