The purpose of this application, under Articles 65.2.1 and 65.2.2 of the Code, is to conserve the usage of the widely used generic name Neobisium Chamberlin, 1930 and of the family-group names neobisiinae Chamberlin, 1930, neobisiidae Chamberlin, 1930 and neobisioidea Chamberlin, 1930. These names are threatened by an overlooked fixation (by monotypy) of Chelifer trombidioides Latreille, 1804 as the type species of Obisium Leach, 1814 (a junior homonym of Obisium Illiger in Kugelann and Illiger, 1798) and hence of its replacement, Neobisium. Chelifer trombidioides is a senior objective synonym of Obisium orthodactylum Leach, 1817, the type species of Chthonius C.L. Koch, 1843 by subsequent designation of Simon (1879), which makes Neobisium a junior objective synonym of Chthonius. Consequently, family-group names based on Neobisium (currently in use up to superfamilial level) would become junior objective synonyms of those based on Chthonius. In order to maintain current usage of the names concerned, it is proposed that Obisium muscorum Leach, 1817 be designated as the type species of Obisium Leach, 1814.