European chiropteromyzid flies (Diptera: Acalyptrata: Heleomyzidae) are revised to clarify their nomenclature, taxonomic concepts and relationships. Two species are recognized which are considered to belong to the genus Neossos Malloch, 1927 viz., the widespread N. broersei (de Meijere, 1946) comb. nov. (= Chiropteromyza wegelii Frey, 1952) and N. nidicola (Frey, 1930) known only from type series from Finland. Consequently, the monotypic genera Ornitholeria Frey, 1930 (type species: O. nidicola Frey, 1930) and Chiropteromyza Frey, 1952 (type species: C. wegelii Frey, 1952) are treated as junior synonyms of Neossos Malloch, 1927. The above synonymies and generic affiliations are confirmed on the basis of comparative morphology of both European species and N. marylandicus Malloch, 1927, the type species of the genus Neossos. All studied taxa are redescribed and illustrated including detail of the male genitalia and/or female postabdomen, keyed and their full synonymies are presented. Preimaginal stages (3^rd-instar larva, puparium) of N. broersei are studied for the first time. Research history, morphology of terminalia, relationships, biology and distribution of European species are reviewed and/or discussed. Lectotypes of Ornitholeria nidicola Frey, 1930 and Chiropteromyza wegelii Frey, 1952 are designated. Based on similarities in the external morphology, including the male and female terminalia, and the cephalopharyngeal skeleton of the larva, chiropteromyzids are considered to be a heleomyzoid lineage most closely related to the subfamily Heleomyzinae (of European authors) and, hence, not deserving family rank within Acalyptrata.