216 Bulletin American Museum of Natural History. [Vol. XXXIV, 
Subgenus Mesosciurus. 
Mesosciurus hoffmanni hoffmanni (Peters). 
Text Fig. 5 (p. 162); Plate VIII, Figs. 1-3; Plate XIII, Figs. 11, 12. 
Sciurus estuans var. hoffmannt Prerers, Monatsh. Akad. Wissen. Berlin, 1863 
(1864), p. 654 (Costa Rica).— Tuomas, Proc. Zool. Soc. London, 1880, p. 401 (in 
text), part. 
Sciurus estuans hoffmannt AuuEN, Bull. Amer. Mus. Nat. Hist., III, p. 206, 
April 17, 1891; zbid., IX, p. 35, March 11, 1897 (Costa Rica).— Nexson, Proc. 
Washington Acad. Sci., I, p. 98, pl. i, fig. 7, May 9, 1899 (Costa Rica to valley of 
Upper Rio Cauca). 
Sciurus hoffmanni ALLEN, Bull. U. 8. Geol. Surv. Terr. (Hayden), IV, No. 4, 
p. 885, Dec. 11, 1878 (considered distinct from S. estuwans); Bull. Amer. Mus. Nat. 
Hist., XX XI, p. 90, April 19, 1912 (Cauca, Colombia) — LONNBERG, Ark. for Zool., 
VIII, No. 16, p. 25, July 12, 1913 (Nanegal and Gualea, Ecuador). 
Sciurus (Guerlinguetus) hoffmannt AtteN, Bull. Amer. Mus. Nat. Hist., XX, 
pp. 44, 66, Feb. 29, 1904, part, (Costa Rica; Chiriqui, Panama; Cauca Valley, 
Colombia). Sciwrus (Guerlinguetus) estuans chiriquensis Bangs referred to hoff- 
manni at p. 66. 
Sciurus estuans var. rufoniger ALLEN, Mon. N. Amer. Rodentia, p. 757, 1877, 
part (Costa Rica references only. Not of Gray 1842, nor of Pucheran 1845). 
Sciurus estuans Aston, Biol. Cent.-Amer., Mamm., p. 132, pl. xiii, June, 1880, 
part (Sciurus griseogenys on plate).— Tuomas, Proc. Zool. Soc. London, 1880, p. 400 
(Intac and Balzar Mts., Ecuador). 
Macroxus xanthotus Gray, Ann. and Mag. Nat. Hist. (3), XX, p. 429, Dec. 1867 
(Costa Rica. Type examined). 
Sciurus griseogenys Auston, Proc. Zool. Soc. London, 1878, p. 667, part; Biol. 
Centr.-Amer., Mamm., pl. xiii, June, 1880. 
Sciurus hoffmanni séderstrémi Stone, Proc. Acad. Nat. Sci. Philadelphia, LX VI, 
p. 14, March 31, 1914 (Mt. Pichincha”’). Type examined. 
Type locality.— “Costa Rica”; no definite locality indicated. The 
type region is here assumed to be the vicinity of San José, at altitudes above 
3000 feet (see p. 218). 
Geographic destribution.— Costa Rica and the Western Andes of Colom- 
bia, south through central Ecuador to Bolivia; not known to occur in 
southern Panama, nor in the lowlands of northwestern Colombia. 
Description.— Pelage of medium length and softness. Postauricular 
patches present but usually not conspicuous. 
Upperparts pale yellowish brown to rufescent brown, the hairs dark 
brown narrowly ringed at the tip with pale yellow varying (in different 
specimens) to rusty yellow; middle of the back often a little darker than 
the sides, sometimes a distinctly darker median band; outer surface of legs 
and teet nearly like the flanks; a narrow yellowish eyering; underparts 
