1917.] Chapman, Distribution of Bird-life in Colombia. 365 



The character of " under tail-coverts cinereous with a white apical edge 

 preceded by a distinct blackish subterminal band" holds good for four of 

 our five males. In the fifth (from Villa vicencio), the lower tail-coverts do 

 not differ materially from those of average Pacific coast males. The bill, 

 however, is perceptibly smaller than in true transandeana. 



Two females (Buena Vista, 1; Villavicencio, 1) are less deeply colored 

 above than Pacific coast females and show slightly more contrast between 

 the tone of the cap and the color of the back. 



Malena, 1; Honda, 2; Buena Vista (alt. 4500 ft.), 2; Villavicencio, 2. 



(1870) Thamnophilus unicolor (ScL). 



Dysithamnus unicolor Scl., P. Z. S., 1859, p. 141 (Pallatanga, Ecuador); Scl. & 

 Salv., p. Z. S., 1879, p. 524 (Sta. Elena). 



Found by us locally in the Subtropical Zone of all three Ranges. Four- 

 teen females and twenty-two males agree in color with specimens from 

 western Ecuador, but in size specimens from the Bogota region average 

 slightly larger. 



San Antonio, 11 ; Gallera, 4; Cerro Munchique, 2 ; Cocal, 2; Ricaurte. 

 2; Barro Blanco, 2; La Palma, 3; Fusugasuga, 5; Aguadita, 2. 



(1882) Thamnophilus nigriceps Scl. 



Thamno-philus nigriceps ScL.,.P. Z. S., 1868, p. 571; published April, 1869 (New 

 Grenada, "Bogota skin"). 



Thamnophilus virgatus Lawk., Proc. Acad. N. S. Phila., XX, 1868, p. 361; 

 published April 27, 1869 ' (Turbo, e. side Gulf of Darien). 



Inhabits the humid Tropical Zone of northern Colombia from eastern 

 Panama to the Magdalena River. Our series. of twenty-eight specimens 

 shows conclusively that both T. nigriceps and T. virgatus are based on the 

 female of a species of which the male is black, and indicates that there is 

 but one race instead of two in the area in question. 



Sixteen of our specimens are adult males, nine are females, and three 

 are young males in transition plumage from the rufous-backed, black- 



1 1 am indebted to Dr. Richmond for calling my attention to the fact that the publication of that 

 part (No. 6) of the Proceedinn^ in which this description occurs was announced at the meeting of 

 the Academy held April 27, 1869. (C/. Proceedings, 1869, p. 13.) The last part of the Proceedings 

 of the Zoological Society, according to the covers of the numbers of this volume for 1868, was pub- 

 lished in March of the following year. The cover for the third part of this volume, however, bears 

 the date "April, 1869." It does not seem probable, however, that the number, due in March, was 

 issued after April 27, the date of publication of the description of Lawrence's Thamnophilus virgatus, 

 and I therefore accept Sclater's name as, in my opinion, having priority. 



