660 Bulletin American Museum of Natural History. [Vol. XXXIV, 
Am., Aves, I, p. 447) as “yellowish green” and Carriker (Bds. Costa Rica, 
p. 833) speaks of it as “pale pea-green.” The bill of flavirostris, on the 
other hand, is described by Richardson (field labels) as “yellow”; Palmer, 
as quoted by Hellmayr (P. Z. S., 1911, p. 1122), describes it as “light 
yellow,” and Festa, as quoted by Salvadori and Festa (Bull. Mus. Tor., 
XV, 1899, p. 28), gives it as “giallo.” ay 
This yellow color, while somewhat lighter apically, extends to the very 
base of the bill, whereas in holosericeus the bill basally is in whole or part 
more or less plumbeous. | 
The character of size is less diagnostic. Mexican birds, however, 
appear never to be as small as South American ones, but Ridgway’s tables 
of measurement (Bull. 50, IJ, p. 194) include Guatemalan specimens which 
are as small as those from Ecuador. I suspect, however, that some of the 
apparent variations in size noted, both individual and geographic, are due 
to erroneous sexing, since the sexes cannot always be distinguished in color. 
As the appended table shows, our largest specimen of holosericeus is also our 
most southern one, and in the color of the bill also it shows no approach 
toward flavrostris. | 
Hellmayr (J. c.) records a female specimen of ‘‘ Amblycercus holosericeus”’ 
having the “bill ight yellow” from Guineo, Rio Calima, in the Tropical 
Zone of western Colombia, and our specimens of the yellow-billed form are 
from the following localities: 
Colombia: ‘ Bogota,’ 2; El Pifion (9600 ft.), E. Andes near Bogota, 1; Rio 
Toché, Cen. Andes, 1; Los Tambos, Cauca region (Batty), 1; Alto Bonito, 
lower Atrato, 1; Barbacoas,1. Ecuador; Esmeraldas, 4; Naranjo, 2; Santa 
Rosa, 1; Guayaquil, 1. 
Measurements. 
Place Sex Wing Tail Tarsus Culmen 
Tampico, Mex. of 103 109 34 al.5 
Tamiahua Lag., Mex. eh 100.5 108 33.5 30 
Gatun, Panama os 103 99 34 29.5 
La Chorrera, Panama op 105.5 — 32.5 30.5 
El Real, a of 106 98.5 34 33 
Esmeraldas, Ecuador os 99 92 dl 29.5 
a : of 98 96 30 29 
Naranjo, 8 ee 98 96 32.5 28 
Guayaquil, A of 96 92 30 31 
Jalapa, Mexico 2 89 98 31 27 
Tlacotalpam, Mexico Q 94 96 31.5 29 
Kl Pifon (near Bogota), Col. Q 82 88 28.5 24.5 
Rio Toché, Col. 2 83 87 30 24.5 
Barbacoas, “ Q 89 92 30 29 
Eismeraldas, Ee. Q 92 95 30 28 
Santa Rosa, “ 2 87.5 86 30 26 
Naranjo, e Q 83 82 29 26 
