Two new species from the superfamily Crotonioidea, Malaconothrus kawensis n. sp. and Cyrthermannia bifurcata n. sp., found in material colected in Kaw mountains (Montagne de Kaw), and near the Saul, French Guyana, are described. The relationships of both new species within respective genera are analysed, and determination keys are provided for all South-American and other closely related Malaconothrus species and for all known Cyrthermannia species.
Cyrthermannia formosana Tseng, 1982 is newly recombined as Nanhermannia (Nippohermannia) formosana (Tseng, 1982) n. comb., following analysis of morphological characters.