No. 9 | BIRDS OF ISLA COIBA, PANAMA—WETMORE . ¥ 59 
a line of dusky neutral gray along the feather shafts; circlet around 
edge of eyelids light buff, barred lightly with dusky neutral gray on 
upper lid; malar region and side of neck warm buff; throat and fore- 
neck warm buff, with the feathers light buff at base, a few with an 
indistinct shaft streak of dark neutral gray; chest, sides, and under 
tail coverts ochraceous-tawny ; lower breast and abdomen slightly 
darker than ochraceous-buff ; edge of wing russet; under wing cov- 
erts ochraceous-buff, the distal ones slightly paler. Maxilla dull black; 
mandible fuscous, grayer at tip, with the cutting edge drab-gray; 
tarsus and toes dusky neutral gray (from dried skin). 
Measurements.—Males (7 specimens), wing 69.9-72.3 (71.0), tail 
54.2-57-7 (56.0), culmen from base 20.3-22.7 (21.1), tarsus 26.4- 
27.8 (27.1) mm. Females (8 specimens), wing 66.9-71.0 (68.9), tail 
53-0-58.5 (54.7), culmen from base 20.9-22.4 (21.5), tarsus 25.7-27.8 
(26.7) mm. 
Type, female, wing 69.8, tail 55.6, culmen from base 22.4, tarsus 
26.7 mm. 
Range.—Isla Coiba, off the Pacific coast of Veraguas, Panama. 
Remarks.—The definitely darker coloration that marks this race 
when compared with Thamnophilus doliatus nigricristatus, though 
readily evident in both sexes, is particularly outstanding in the female. 
For this reason it has seemed desirable to select a female specimen 
as type. The male has the black bars of the lower surface wider 
than in nigricristatus, and also has the markings extended across the 
abdomen with little diminution in amount, so that this area is only 
slightly, if at all, less heavily barred than the rest of the lower sur- 
face. The throat also is more heavily marked with streakings of 
black. The birds agree with nigricristatus, and differ from T. d. 
pacificus in having only a relatively small amount of white concealed 
in the bases of the black crown feathers. 
While comparison in the diagnosis has been made with T. d. 
nigricristatus of the adjacent mainland, the darker coloration is 
rather more similar to the condition found in the distantly located 
T. d. intermedius, which ranges from eastern Costa Rica and eastern 
Nicaragua north to Tamaulipas and San Luis Potosi. The male inter- 
medius, however, has extensive white markings concealed in the 
crown, and also averages larger, except in the bill, which is slightly 
heavier in the birds from Coiba. The female of eremnus differs from 
intermedius, as it does from nigricristatus, in much darker color. 
The subspecific name of the form here described is taken from 
the Latin adjective eremnus, swarthy, or dark. 
