BIRDS FROM BRAZIL AND SOUTHERN VENEZUELA—FRIEDMANN 415 
any other regions.’”’ The five Brazilian skins have been compared 
with specimens of N. a. derbyanus, with which they also disagree. 
It is possible that they represent an undescribed race, although how 
they differ from those individuals of albicollis that fit the description 
of obscurus is difficult to see. 
CAPRIMULGUS NIGRESCENS NIGRESCENS Cabanis: Dark Nighthawk 
Caprimulgus nigrescens CABANIS, in Schomburgk, Reisen in Britisch-Guiana ...; 
pt. 3, 1848, p. 710 (Lower Essequibo River, British Guiana), 
SPECIMENS COLLECTED 
lad. 9, Brazil, Rio Cauabury, October 31, 1930. 
lad. 2, Brazil, Rio Maturacd, November 8, 1930. 
2ad. o’,2ad. 9, Brazil, S40 Gabriel, Rio Negro, December 30, 1930—January 6, 
1931. : 
lad. o’, Venezuela, San Carlos, Rio Negro, January 28, 1931. 
1 ad. o’, Venezuela, Puerto Ayacucho, Upper Orinoco, January 8, 1930. 
The Puerto Ayacucho bird was in breeding condition when collected. 
In the absence of adequate comparative material, we follow Peters 
(Check list of birds of the world, vol. 4, 1940, p. 202) in considering 
C. n. duidae Griscom and Greenway a synonym of this race, with, 
however, due notice of the fact that the two describers stick to their 
original conception of the races of this nighthawk in a paper sub- 
sequent to Peters’ volume (Bull. Mus. Comp. Zool., vol. 88, 1941, 
pp. 164-165). If future work should uphold duidae the present 
series would have to be referred to it. 
HYDROPSALIS CLIMACOCERCA SCHOMBURGEI Sclater: Schomburgk’s Nighthawk 
Hydropsalis schomburgki ‘‘G. R. Gray’? Scuater, Proc. Zool. Soc. London, 1866; 
p. 142 (British Guiana). 
SPECIMENS COLLECTED 
lad. 9, Brazil, Rio Cauabury, Cachoeira Thomaz, October 26, 1930. 
1 ad. 9, Brazil, Rio Cauabury, below Cachoeira Destacamento, October 28, 
1930. 
1 ad. o', 1 ad. 9, Brazil, Rio Cauabury, Cachoeira Destacamento, October 
29 and December 14, 1930. 
lad. 9, Venezuela, Isla Yagrumo, Rio Negro, January 25, 1931. 
lad. o&, 1 ad. 9, Venezuela, Santa Rosa, Rio Negro, January 26, 1931. 
lad. @, Venezuela, below San Carlos, Rio Negro, January 27, 1931. 
lad. &, Venezuela, Brazo Casiquiare, Raudal San Sebastian, February 1, 1931. 
lad. o, Venezuela, Brazo Casiquiare, near Cafio Perro de Agua, February 18, 
1931. 
lad. @, lad. 9, Venezuela, Brazo Casiquiare, Buenos Aires, February 21, 1931. 
Most of the examples collected in January and February were 
noted as being in breeding condition. 
This series varies very considerably, so much so, in fact, that 
one is led to wonder if possibly it may be a migratory species and 
that more than one race is here represented. The three males from 
