The mountain midges (Diptera: Deuterophlebiidae) of the Palaearctic Region are revised to include eight species. Four new species are described: D. brachyrhina sp. nov., D.oporina sp. nov. and D. blepharis sp.nov. from the Himalayas (Assam and Sikkim), and D.bicarinata sp. nov. from southern Korea. A lectotype is designated for D.mirabilis Edwards, and a key to adult males of all Palaearctic species is provided.

Larval, pupal and adult characters were used to reconstruct the phylogenetic and biogeographic relationships of world species of Deuterophlebiidae. Based on features of the adult male, the Himalayan species D. brachyrhina and D. oporina are considered the most primitive deuterophlebiids. The Nearctic species D. inyoensis is proposed as the sister group of the remaining species. Relationships among the latter are based primarily on larval and pupal characters; however, lack of information about the immature stages of several Palaearctic species contributes to a poorly resolved phylogeny. Several alternative hypotheses are presented and discussed. All phylogenetic alternatives suggest that the Nearctic fauna originated from at least two invasions of North America.