The tcttigoniine katydids of South America are reviewed. All species occur in Chile and adjacent Argentina. Four tettigoniine genera are recognized from South America. Calodectes gen.n. with 1 species from Chile, crybeloplatus sp. n., is unrelated to any other. Xyrdectes gen. n. contains 2 species from Chile, type-species chileno sp. n. and fuscescens (Blanchard), comb. n. Falcidectes gen. n. is from Chile with 2 species, type-species divisus sp. n. and xyelus sp. n.; however, nymphs indicate more may exist. Platydecticus Chopard with 15 species, type-species angustifrons Chopard from Argentina and Chile, gubernaculus sp. n., hubbelli sp. n., mammantus sp. n., manacus sp. n., onax sp.n., philopenus sp. n., primnocaudus sp.n., sagariferus sp.n., pheroxiphus sp. n., robertsi sp. n., rupicolus sp. n., simplex sp. n., tumidiplatus sp. n., and darwini sp. n. all from Chile. The relationships of the genera are found to be with Australia and western North America (genus Neduba Walker). None of the genera shows links with Africa. A similar-looking genus and species from Chile, Coniungoptera gen. n. (type-species nothofagi sp.n.) associated with Nothofagus, is nearest related to Metholce Walker and Veria Walker of Australia, and a new tribe, Coniungopterini is proposed for these three genera of Conocephalinae.