The European genus Onychiuroides Bagnall, 1948 is revised. The genus is defined within the subfamily Onychiurinae on the basis of the arrangement of the dorsal posterior cephalic pseudocelli (set in a triangle), presence of 11 setae in the distal whorl of tibiotarsi and the structure of the reduced furca (finely granulated area with 1+1 setulae posteriorly, in contact with the border between abdominal sterna III and IV). Seven new species are described (O. igori sp. n., O. pirinensis sp. n., O. paoloi sp. n., O. cerberus sp. n., O. bojani sp. n., O. peteri sp. n. and O. occultus sp. n.). Nine previously known species are redescribed on the basis of types and new specimens [O. anelli (Denis, 1938), O. bureschi (Handschin, 1928) comb. nov., O. canzianus (Stach, 1934) comb. nov., O. hrabei (Rusek, 1963) comb. nov., O. papillaeferus (Stach, 1946) comb. nov., O. postumicus (Bonet, 1931) comb. nov., O. pseudogranulosus (Gisin, 1951), O. quadripapillatus (Rusek, 1965) comb. nov., O. subgranulosus (Gama, 1964) comb. nov., O. vornatscheri (Stach, 1946) comb. nov.]. Lectotypes are designated for O. anelli and O. vornatscheri. O. paucituberculatus (Stach, 1934) comb. nov., O. beroni (Gruia, 1972) comb. nov. and O. multisetis (Gruia, 1971) stat. & comb. nov. are transferred to the genus Onychiuroides after analysis of the original description. Onychiurus granulosus denticulatus Salmon, 1964 is junior synonym of O. granulosus (Stach, 1930). O. longisetosus (Stach, 1954) comb. nov. is regarded as “species inquirenda”. An identification key to all Onychiuroides species is provided.

The history of the genus Onychiurus is discussed. Four new Onychiurus species are described from North American caves: steinmanni and nathanieli from Colorado, reluctoides from Indiana, and furcisetosus from Virginia. Onychiurus reluctus Christiansen, 1961 is redescribed. A key for all of the known North American species is provided.

An emended diagnosis of Hymenaphorura (Bagnall, 1948) is provided. Eleven new species are described: H. reducta sp. n., H. ridibunda sp. n., H. alaskana sp. n., H. granulata sp. n., H. sensitiva sp. n., H. superba sp. n., H. nearctica sp. n., H. mystica sp. n., H. teretis sp. n., H. anatolii sp. n., H. palaearctica sp. n. H. similis (Folsom, 1917) is redescribed on the basis of type material. Descriptions of H. sibirica (Tullberg, 1876), H. cocklei (Folsom, 1908) and H. decus (Christiansen & Bellinger, 1980) are supplemented. An identification key for all the known species of the genus is given.

Endonura taurica (Stach, 1951) and E. quadriseta Cassagnau et Péja, 1979 are redescribed based on types and material from the Crimea (Ukraine) and Turkey. Endonura gracilirostris sp. nov and E. dentifera sp. nov. are described from the Crimea (Ukraine).