Revision of the New Zealand species of Hydropeza Sinclair (Diptera : Empidoidea : Ragas-group)

Abstract

The New Zealand species of Hydropeza Sinclair are revised and include the following ten species: H. agnetis, sp. nov., H. akatarawa, sp. nov., H. clarae, sp. nov., H. daviesi, sp. nov., H. longipennae (Miller), H. milleri, sp. nov., H. paniculata, sp. nov., H. tutoko, sp. nov., H. vockerothi, sp. nov. and H. wardi, sp. nov. All species are described and male genitalia illustrated. Adults skate about on pools and below small cascades in cool montane streams. The New Zealand fauna is divided into two groups, with the H. longipennae-group assigned as the sister-group to all remaining species of the genus. Only one species is currently known from North Island, with all remaining species confined primarily to west of the Alpine Fault in South Island. The distribution patterns in South Island are examined and implications discussed.