The genua Roquettea Mello-Leitão, hitherto monotypic and known from Brazilian state of Pará, is rediagnosed, the type species, Roquettea singularis is redescribed, including a report on two male morphs, being the second record of male polymorphism in Cosmetidae, the first in South America. Three new species are described from northern Brazil — Roquettea taurine n. sp. (which possesses a unique horned ocularium) and Roquettea jalapensis n. sp. (without notable scutal structures), both from the state of Tocantins, being the first record of the family Cosmetidae from Tocantins; and Roquettea scrotalis n. sp. (with a unique 2-balled dorsal tuberous complex) from Amapá state, being the first record of the subfamily Discosomaticinae from Amapá. Roquettea is compared to the closely related genus Gryne, both currently placed in Discosomaticinae, and also to Profus, the type genus of the subfamily. The unity of Discosomaticinae is discussed, and evidence for the monophyly of this subfamily is weak at best. Male genitalia are for the first time illustrated and described for genera Protus, Roquettea and Gryne, and SEM micrographs are used for the first time in descriptions of Cosmetidae.