A taxonomic revision of the askoldella species-group of the genus Nemophora Hoffmannsegg (Lepidoptera: Adelidae)

A group of externally very similar, grey species of the genus Nemophora Hoffmannsegg, whose females possess a brush of dark scales at the middle of their antenna, is revised. Five species of this group, all distributed in South-East Asia, are recognized: N. griseella (Walsingham) sp. rev. [= cyphozona (Meyrick) syn. n.; = tricrates (Meyrick) syn. n.] from India, Burma and Nepal; N. ichnodesma (Meyrick) comb. n. from India and W Malaysia; N. cassiterites (Meyrick) comb. n. from India only; N. askoldella (Milliere) [= irroratella (Christoph); = niphites (Meyrick) syn. n.] from China, S Korea, Japan, Khabarovsk and Primorye regions of Russia; N. chionites (Meyrick) comb. n. from India and Thailand. Data on all primary types are provided; lectotypes are designated where necessary. The monophyly of the group and the relationships of its species are discussed. Keys to species based on external characters and male genitalia are provided; adults and male genitalia are described and illustrated.