Abstract
On the basis of new morphological data a re-description of the genus Pelodiaetus is provided, a new species of the genus P. nunni sp. nov. (Christchurch, Canterbury, South Island) is described, and P. lewisi Jeannel is proposed as a synonym of P. sulcatipennis Jeannel, syn. nov. A taxonomic key as well as distribution maps for species of Pelodiaetus are provided. Data on comparative morphology and biogeographical aspects of speciation in the genus Pelodiaetus and its morphological relatives from Australia and New Zealand are discussed.