The purpose of this application, under Article 75.5 of the Code, is to conserve the usage of the name Chionobas chryxus Doubleday, 1849 (currently Oeneis chryxus) in its original and accustomed usage for a nymphalid butterfly from the Rocky Mountains by designation of an identifiable neotype. Chionobas chryxus Doubleday 1849 (currently Oeneis chryxus) was described and figured from a male specimen which has since been lost. The original figure perfectly matches males of one of the two species into which the species was later divided. In 1984 a female specimen was designated as lectotype but the lectotype lacks adequate locality data and is a female so cannot be determined as either of the two segregate species, and the validity of this designation under Article 72.4.1.1 of the Code is unclear. It is proposed that all previous type fixations for the species Chionobas chryxus be set aside and a male specimen identifiable as the species proposed in the original publication be designated as neotype.