56 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
tawny. Maxilla fuscous; mandible deep olive-buff; tarsus and toes 
Chaetura black; claws drab (from dried skin). 
Measurements.—Males (3 specimens), wing 62.8-65.8 (64.1), tail 
59.6-61.4 (60.3), culmen from base 14.0-15.4 (14.8), tarsus 17.2-18.0 
(17.7) mm. Females (3 specimens), wing 61.6-62.4 (61.9), tail 58.2- 
60.3 (59.5), culmen from base 14.6-15.3 (15.1), tarsus 17.0-17.8 
(17.4) mm. 
Type, male, wing 65.8, tail 61.4, culmen from base 14.9, tarsus 
17.2 mm. 
Range.—lIsla Coiba, off the Pacific coast of Veraguas, Panama. 
Remarks.—The general appearance of this bird, a remarkable ad- 
dition to the Panamanian avifauna, is that of the group of forms 
allocated under the species name Cranioleuca vulpina (Pelzeln), 
though the decidedly brighter brown of the lower surface separates it 
from them so definitely as almost to warrant species status. The 
distribution of C. vulpina is mainly in Brasil, the most northern of 
its races previously known, C. v. alopecias (Pelzeln) and C. vw. 
apurensis Zimmer and Phelps, extending only into the Orinoco 
Valley. In southern Venezuela, it is recorded from San Fernando de 
Atabapo and the Apure and Arauco Rivers to the lower Orinoco, 
coming barely within the limits of eastern Colombia at Maipures, 
near the mouth of the Rio Vichada. The population resident on Isla 
Coiba thus is separated from its nearest relatives by the entire width 
of Colombia and the greater part of Panama. 
The name given to the bird found on Coiba is taken from the Latin 
dissitus, lying apart, or remote. 
The allocation of the race described above has entailed a survey 
of Cranioleuca vulpina as a species. In the course of this I have 
noted especially the bird described originally as Synallaxis vulpecula 
by Sclater and Salvin from the Rio Ucayali, Pert, now recognized 
as a member of the genus Cranioleuca and currently allocated as a 
subspecies of C. vulpina. Compared with the other geographic races, 
vulpecula differs widely in the decidedly heavier bill, and in the much 
more distinct pattern of spotting and streaking on the under surface. 
As a character of lesser value, the rump is nearly concolor with the 
back, instead of being quite different in color. On the whole it 
appears that the sum of these differences warrants recognition of 
vulpecula as a separate species, distinct from any others of the genus. 
