ABSTRACT: Abstract The Niphta Theischinger fauna of South America is revised to include 11 species, nine of which are described as new to science (N.acus Pivar, sp. nov., N.bifurcata Pivar & Moulton, sp. nov., N.bispinosa Pivar & Sinclair, sp. nov., N.brunnea Pivar, sp. nov., N.courtneyi Pivar, sp. nov., N.daniellae Pivar, sp. nov., N.downesi Pivar, sp. nov., N.eurydactyla Pivar, sp. nov., N.mapuche Pivar, sp. nov.). The genus Niphta is redefined, both previously described Chilean species are redescribed, N.halteralis (Edwards) and N.nudipennis (Edwards), and females are described or redescribed where possible. The first descriptions of the immature stages of South American Niphta are provided, which represent a new larval morphotype in Thaumaleidae, as larvae and pupae possess ventral adhesive structures. Furthermore, these larvae were collected from vegetation rather than rocky substrates. Illustrations and micrographs are provided for all species, and scanning electron microscopy images are included for select immatures. A key to species, distribution maps, and discussions regarding phylogenetic affinities and habitat are also included.
