540 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no 



Belem and Braganza, Pard, 1 (BM, type of paricola); Recreio, Rio Majary, 

 Amazonas, 1 (AMNH); Urucum de Corumbd, Mato Grosso, 1 (CNHM); Barao 

 Malgago, Mato Grosso, 3 (including type of milleri, AMNH); Urupd, Mato 

 Grosso, 1 (AMNH). 



Oryzomys bicolor phaeotis Thomas 



Rhipidomys phseotis Thomas, Ann. Mag. Nat. Hist., ser. 7, vol. 7, p. 181, 1901. 

 [Oryzomys {(Ecomys)] phseotis, Thomas, Ann. Mag. Nat. Hist., ser. 7, vol. 7, 



p. 445, 1906 (classification). 

 Oryzomys {Oecomys) phaeotis, Sanborn, Publ. Mus. Hist. Nat. "Javier Prado," 



ser. A, zool.. No. 6, p. 21, 1951 (Peru: Marcapata, Cuzco; Camante, Cuzco). 

 Rhipidomys benevolens Thomas, Ann. Mag. Nat. Hist., ser. 7, vol. 7, p. 369, 1901 



(type locality, Chimate, upper Rio Beni, La Paz, Bolivia; altitude, 700 



meters above sea level). 

 [Oryzomys {(Ecomys)] benevolens, Thomas, Ann. Mag. Nat. Hist., ser. 7, vol. 18, 



p. 445, 1906 (classification). 

 Oecomys benevolens, Gyldenstolpe, Kungl. Svenska Vet.-Akad. Handl., ser. 3 



vol. 11, p. 40, pi. 4, fig. 1 (skull), pi. 17, fig. 11 (molars), 1932. 



Type: AduJt male, skin and skull (BM 1.1.1.23); collected July 23, 

 1900, by Perry O. Simons. 



Type locality: "Segrario" [=Sagrario], upper Rio Inambari, an 

 affluent of the Rio Madre de Dios, Puno, southeastern Peru. 



Distribution: Departments of Cuzco, Puno, and Madi-e de Dios 

 in southeastern Peru, and Departments of La Paz, Cochabamba, and 

 Beni in northwestern Bolivia; altitudinal range from approximately 

 200 to 2,000 meters above sea level. 



Characters: Largest of the subspecies; molars proportionately 

 larger. 



Measurements: See table 6. 



Remarks: The available Peruvian specimens of 2>haeotis, including 

 the type and a paratype, are from four localities within a compara- 

 tively small area in the drainage basin of the upper Rio Inambari, an 

 affluent of the Madre de Dios. Two from Camante, Marcapata, 

 taken August 1950, are as large as the type of phaeotis collected July 

 1900. An individual from Quincemil, collected August 1953, and 

 another from Villa Carmen, Cosnipata, dated September 1954, agree 

 with typical bicolor in size. No measurements of the paratype were 

 given but Thomas declared it to be "about the same general size" as 

 the type. The large Camante specimens, judged by cranial charac- 

 ters, are not older than the others and the molars are slightly less worn. 



Rhipidomys benevolens Thomas, from the upper Rio Beni, Bolivia, 

 was characterized as larger than dryas (= occidentalis) and smaller 

 than phaeotis. Representative specimens from the upper Rio Mamor^ 

 include one subadult and three juvenals. They agree with phaeotis 

 in their over-all larger size and proportionately larger molars as com- 

 pared with typical bicolor of northeastern Peru and eastern Ecuador. 



