The purpose of this application, under Article 75.6 of the Code, is to conserve the current usage of the name Tyrophagus putrescentiae (Schrank, 1781) for a ubiquitous, medically and economically important species of acariform mite (family acaridae) by setting aside the existing name-bearing type and designating a replacement neotype. Cultures of this mite species are maintained in many research institutions or companies and are commercially traded as a source of mite allergens, food for phytoseiid mites used in biological control, and for various molecular biology applications. A recent taxonomic treatment indicated that the taxonomic concept of T. putrescentiae involved two closely related species, one common and one rare, and the neotype designated by Robertson (1959) for T. putrescentiae corresponds to the rare species; the common species was renamed as Tyrophagus communis Fan & Zhang, 2007. We demonstrated that the prevailing usage of the name T. putrescentiae comprises almost exclusively the common species, the name T. communis is a junior synonym of eight previously named taxa with extant types, and we proposed a new name for the rare species: Tyrophagus fanetzhangorum Klimov & OConnor, 2009. The stability of zoological nomenclature is therefore threatened by the following: (1) the prevailing usage of the name T. putrescentiae was not maintained by Fan & Zhang (2007); (2) the name T. communis proposed for the common species is a junior synonym and, therefore, not valid; and (3) besides the eight taxa for which synonymy with the common species was verified by us, types of older taxa may also be discovered in the future thus posing another nomenclatural challenge. We propose to conserve the prevailing usage of the name T. putrescentiae by designation of a new neotype from a culture currently maintained in a research institution, which was cited in many published works and started from specimens collected close to the type locality of T. putrescentiae.