1906. =leptus= (_Putorius streatori_) Merriam [= _Mustela erminea murica_], Proc. Biol. Soc. Washington, 16:76, May 29, 1903, until 1945 was applied to the diminutive ermine of the Rocky Mountains from Wyoming south to northern New Mexico but proves to be a synonym of _muricus_ with type locality in the Sierra Nevada of California. 1908. =angustidens= (_Putorius cicognanii_) Brown [= _Mustela erminea angustidens_], Mem. Amer. Mus. Nat. Hist., 9(pt. 4):181, pl. 17, is applied to an extinct subspecies known from fossil remains of Pleistocene age from northern Arkansas. 1908. =gracilis= (_Putorius_) Brown [= _Mustela frenata gracilis_], Mem. Amer. Mus. Nat. Hist., 9(pt. 4):182, 1908, applies to a Pleistocene weasel known from a single skull from northern Arkansas. 1912. =costaricensis= (_Mustela_) Goldman [= _Mustela frenata costaricensis_], Proc. Biol. Soc. Washington, 25:9, January 23, 1912, applies to the long-tailed weasel of Costa Rica. 1913. =primulina= (_Mustela_) Jackson [= _Mustela frenata primulina_], Proc. Biol. Soc. Washington, 26:123, May 21, 1913, applies to the long-tailed weasel of the central part of the United States in eastern Kansas and adjoining areas. 1913. =campestris= (_Mustela_) Jackson [= _Mustela rixosa campestris_], Proc. Biol. Soc. Washington, 26:124, May 21, 1913, applies to the least weasel of the Great Plains region. 1913. =olivacea= (_Mustela peninsulae_) Howell [= _Mustela frenata olivacea_], Proc. Biol. Soc. Washington, 26:139, May 21, 1913, applies to the long-tailed weasel of the southeastern United States excepting most of Florida. 1914. =meridana= (_Mustela_) Hollister [= _Mustela frenata meridana_], Proc. Biol. Soc. Washington, 27:143, July 10, 1914, applies to the long-tailed weasel of northern South America. 1916. =nicaraguae= (_Mustela tropicalis_) Allen [= _Mustela frenata nicaraguae_], Bull. Amer. Mus. Nat. Hist., 35:100, April 28, 1916, applies to the long-tailed weasel of Nicaragua. 1927. =arthuri= (_Mustela noveboracensis_) Hall [= _Mustela frenata arthuri_], Proc. Biol. Soc. Washington, 40:193, December 2, 1927, applies to the long-tailed weasel of Louisiana and adjoining areas. 1932. =semplei= (_Mustela arctica_) Sutton and Hamilton [= _Mustela erminea semplei_], Ann. Carnegie Mus., 21(2):79, February 13, 1932, originally was applied to the ermine of Southampton Island but after 1945 was applied also to the ermine of Baffin Island, Melville Peninsula and the west side of Hudsons Bay as far south as Eskimo Point. 1932. =panamensis= (_Mustela frenata_) Hall, Proc. Biol. Soc. Washington, 45:139, September 9, 1932, applies to the long-tailed weasel of Panamá.