Vol. XXIX, pp. 155-156 September 6, 1916 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



A NEW VESPER RAT FROM NICARAGUA. 

 BY E. A. GOLDMAN. 



The vesper rats of the genus Nyctomys are restricted in distri- 

 bution to the Central American Subregion, the combined ranges 

 of known forms extending from central Vera Cruz, Mexico, to 

 western Panama. They are handsome, arboreal rodents, char- 

 acterized externally by bright ochraceous-buffy or ochraceous- 

 tawny upperparts and sharply contrasting white underparts. 

 The tail is rather short and well furred ; the feet are short and 

 stout as in the allied genus Rhipiclomys, and the compressed, 

 recurved claws exhibit adaptation for climbing. 



Owing doubtless to arboreal habits comparatively few examples 

 of the genus are obtained by collectors. Specimens taken by 

 Dr. C. W. Richmond in the humid Atlantic coast region of 

 Nicaragua more than 20 years ago represent a new form, 

 described below: 



Nyctomys sumichrasti venustulus subsp. nov. 



Type from Greytown, Nicaragua. No. IrTfl) ? adult, U. S. National 

 Museum (Biological Survey Collection), collected by C. W. Richmond, 

 February 10, 1892. Original number 17. 



General characters. — Color of upperparts decidedly darker than in 

 N. s. sumichrasti, N. s. salvini, N. s. decolorus, or N. s. nitellinus; skull 

 very broad. 



Color. — Type: Upperparts near tawny of Ridgway (1912), finely and 

 rather inconspicuously mixed with black, the general tone darkest on 

 top of head and over back, becoming somewhat paler along flanks and 

 outer sides of limbs; underparts white; ears, orbital borders, and small 

 antorbital areas black; fore feet dull white; toes and plantar borders of 

 hind feet whitish, the median metapodial areas blackish as usual in the 

 genus; tail unicolor, brownish black. 



Skull. — Similar in general to those of N. s. sumichrasti and the other 



30— Proc. Biol. Soc. Wash.. Vol. XXIX, 1916. (155) 



