268 Bulletin American Museum of Natural History. [Vol. XXXIV, 
separation from the typical forms of Urosciurus. It also occupies a different 
faunal area, its range being outside and south of the great Amazonian forest 
region, which constitutes the principal range of the genus. 
Species and Subspecies of Urosciurus, with type localities and statement of 
number of specimens examined. 
Urosciurus tricolor (Poeppig). Maynas, near junction of Huallaga and 
Marafion Rivers. Specimens examined, 3. | 
Uroscturus duida (Allen). Southern base of Mount Duida, Venezuela. 
Specimens examined, 3. 
Urosciurus igniventris igniventris (Wagner). Maribitanos, Upper Rio 
Negro, Brazil. Specimens examined, 5. 
Urosciurus igniventris tedifer (Thomas). Bogota district, Colombia. 
Specimens examined, 1. 
Urosciurus igniventris cocalis (Thomas). Near junction of Rio Coco 
and Rio Napo, Ecuador. Specimens examined, 2. 
Urosciurus igniventris zamore (Allen). Zamora, Ecuador. Specimens 
examined, |. 
Urosciurus pyrrhonotus pyrrhonotus (Wagner). Borba, Brazil, near 
mouth of Rio Madeira. Specimens examined, 1. 
Urosciurus pyrrhonotus castus (Thomas). Chimate, Bolivia. Speci- 
mens examined, 1. 
Urosciurus langsdorffii langsdorfia (Brandt). “Brasilia” = Cuyaba, 
Matto Grosso, Brazil. Specimens examined, 16. 
Urosciurus langsdorffit urucumus (Allen). Urucum, Matto Grosso, 
Brazil. Specimens examined, 11. 
Urosciurus langsdorffii steinbachi (Allen). Sta. Cruz de la Sierra, 
Bolivia. Specimens examined, 5. 
Key to the Species and Subspecies of Urosciurus. 
Skull with rostrum very long and narrow. 
Upperparts dark brown or blackish, washed with ochraceous; underparts pale 
PO MOM MN sod Md ck Se ene Onk wnat ipa gpk cor etery eee tricolor (p. 269) 
Upperparts lighter, washed with yellowish gray; underparts dark ferruginous 
| duida (p. 270) 
Skull with rostrum shorter. 
Upperparts heavily washed with ochraceous; head ochraceous rufous; under- 
parts ferruginous. 
Tail with basal third deep black, rest heavily fringed with reddish 
orange, concealing the black basal portion of the hairs. 
rgniventris (p. 271) 
