Two new species, Prolixus nicholasi sp. nov. and Prolixus setifolius sp. nov., are described and illustrated from leaves of Gahnia setifolia (Cyperaceae) in Auckland, New Zealand. In this paper, we present the ontogenetic additions in idiosomal and the leg chaetotaxy from larva to adult. The adult male and female of P. setifolius have different leg setae, allowing all active life stages to be sexed. A key to world species of Prolixus is also proposed.