Thaumaleidae (Diptera) collected by the late Dr. W. Joost in the Caucasus Mountains.

The aquatic insect collection of the late Dr. W. Joost contained two new species of Thaumaleidae (Diptera) from the Caucasus Mountains: Thaumalea monikae sp. n. and Thaumalea biacuminata sp. n. These two new species are herein described, and the most abundant species in Dr. Joost's collection, Thaumalea martinovskyi Joost, 1979, is redescribed based on the type material. Figures of male and female genitalia for all species are provided. All three species show morphological similarities to taxa from the Eastern Mediterranean area. Thaumalea monikae is related to the European T. bezzii-species group, T. biacuminata to the T. serrata-group, and T. martinovskyi to T. kyladica Wagner, 1981 and T. malickyi Theischinger, 1979 from the Eastern Mediterranean area.