In a collection of terrestrial isopods from Venezuela, a distinct species was identified which does not fit any of the known genera. Therefore, a new taxon Metaprosekia gen.n. is instituted to accomodate the new species. An analysis of its morphological characters revealed a close relationship to the genus Prosekia Vandel, 1968 and allied genera. The phylogeny of this group is discussed and one of its poorly known representatives, Xiphoniscus mirabilis Vandel, 1968 is redescribed on the basis of the type material.