414 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 97 
SPECIMEN COLLECTED 
lad. 9, Venezuela, Isla Yagrumo, Rio Negro, January 25, 1931. 
This example has the small measurements of the northern race, 
to which, by geography, it should belong. It is in rather worn 
plumage. 
LUROCALIS SEMITORQUATUS SEMITOROUATUS (Gmelin): Semicollared Nighthawk 
Caprimulgus semitorquatus GMELIN, Systema naturae, vol. 1, pt. 2, 1789, p. 1031 
(Cayenne). 
SPECIMEN COLLECTED 
1 ad. o’, Venezuela, San Carlos, Rio Negro, January 28, 1931. 
The single specimen obtained is in worn plumage, the feathers of 
the interscapular and upper back areas being particularly abraded. — 
NYCTIDROMUS ALBICOLLIS ALBICOLLIS (Gmelin): Cayenne Parauque 
Caprimulgus albicollis GMELIN, Systema naturae, vol. 1, 1789, p. 1030 (Cayenne). 
SPECIMENS COLLECTED 
2ad. o, lim. co, lad. 9, Brazil, Santa Isabel, Rio Negro, October 10-138, 1930. 
lad. 9, Brazil, Sao Gabriel, Rio Negro, January 12, 1931. 
3 ad. o’, Venezuela, San Carlos, Rio Negro, January 28. 
lad. 6, 1 ad. -, Venezuela, Cerro Yapacana, Upper Orinoco, April 5-29, 1931. 
lad. o&, lad. 9, Venezuela, Puerto Ayacucho, Rio Orinoco, May 9-16, 1931. 
Some of the specimens taken in January, February, and May were 
noted as having enlarged, active gonads when collected. 
All the Venezuelan specimens are in the rufescent phase, the 
rufescent color being especially strong on the throat and upper 
breast. The most variable feature is the color of the crown, occiput, 
nape, and interscapulars, which varies from pale tawny in one male 
to sayal brown tinged with gray in another, and to light drab tinged 
with avellaneous in another. 
The Brazilian examples include birds in both the gray and the 
rufescent phase. They average a little darker than the Venezuelan 
birds (comparing only birds in the same phase) and appear to con- 
stitute what may prove to be a recognizable local form. Unfortu- 
nately they appear to correspond to the characters of the Peruvian 
form N. a. obscurus Cory. Zimmer (Publ. Field Mus. Nat. Hist., 
Zool. Ser., vol. 17, 1930, p. 268), however, found that obscurus was 
not separable from albicollis. He had the type of obscurus available 
for study and found that there was “great variation in coloration 
throughout the series, with the two extremes of brown and sooty 
plumage quite different when compared with each other, but there 
are intermediates of every stage. The type of obscurus is a dark 
bird but it can be matched by specimens from near the type locality 
of albicollis while other Peruvian skins are as light in color as from 
