386 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 97 
SPECIMEN COLLECTED 
1 ad. 9, Venezuela, near Soledad, Anzodtegui, December 1, 1929. 
The short wing length of this example, 418 mm., shows that the 
bird is of the race colonus to which it should belong on geographic 
grounds. It is a fully adult bird in good plumage. Gilliard (Bull. 
Amer. Mus. Nat. Hist., vol. 77, 1941, p. 458) has recorded colonus 
from as far south as Mount Auydn-tepui, and lists it from Maripa, 
about a hundred miles west of Soledad. It gets to Pard (Ilha Marajé) 
on the Lower Amazon, but Griscom and Greenway find (Bull. Mus. 
Comp. Zool., vol. 88, 1941, p. 112) that a bird from the Tapajéz is 
referable to B. a. albicaudatus. They write that the two forms meet 
in lower Amazonia. 
BUTEO MAGNIROSTRIS MAGNIROSTRIS (Gmelin): Insect Hawk 
Falco magnirostris GMELIN, Systema naturae, vol. 1, pt. 1, 1788, p. 282 (Cayenne). 
SPECIMENS COLLECTED: 
lad. 3, Venezuela, Brazo Casiquiare, Playa de Candela, February 8, 1931. 
1 ad. o&, Venezuela, Upper Orinoco, near Cerro Cariche, February 24, 1931. 
lad. o, lad. 9, Venezuela, Upper Orinoco, opposite Corocoro Island, March 
12-16, 1931. 
1 ad. 6, 1 ad. 9, Venezuela, Cerro Yapacana, Upper Orinoco, April 27-29, 
1931. 
4ad. o', lim. &, 2ad. 9, Venezuela, Puerto Ayacucho, Rfo Orinoco, January 
2, 19380, and May 11-21, 1931. 
lad. 9, Venezuela, Ciudad Bolivar, December 8, 1929. 
This excellent series secured between the Casiquiare and Ciudad 
Bolivar averages slightly darker above than true magnirostris as 
represented by specimens from British Guiana and may eventually 
prove to be an undescribed race. With the present material it seems 
best to refer them to the nominate subspecies as the forms of this 
hawk in South America are not too well defined or understood at the 
present time. 
The bars on the thighs of the adult males are very variable, ap- 
parently without regard to geography. Thus, in some specimens 
from the Casiquiare and the Upper Orinoco the dark bars are very 
narrow and dull, rather light olive-brown, while in others from the 
Upper Orinoco they are much broader and tawny-rufescent. Inas- 
much as the bird is not known to be migratory, one can look upon this 
only as individual variation. 
The adult female from the Upper Orinoco, opposite Corocoro 
Island, March 16, is quite different from all the other specimens in 
the present series in its dark, distinctly brownish-gray coloration 
on the upperparts and in having much darker bars on the under- 
parts. 
