Bulletin - United States National Museum - si-pddr - Smithsonian ...

302 BULLETIN 133, UNITED STATES NATIONAL MUSEUM
common on the plains that bordered the Rio Negro. Females were
prepared as skins on November 23 and 24, and two additional speci-
mens, one as a skeleton and one in alcohol, were preserved.
They ran swiftly along on the ground to pause and stand with
head erect, or perched in alert attitudes on fence wires or the tops
of bushes. In flight they traveled for long distances barely above
the ground to rise finally to a perch on a low bush. Males at inter-
vals flew up to make a metallic rattle with their wings as they
turned abruptly and dropped to the ground.
Near Zapala, Neuquen, from December 7 to 9, these flycatchers
were observed in little valleys where the grass had been closely
cropped by stock. An adult male was taken December 7. Near In-
geniero White, the port of Bahia Blanca, Buenos Aires, probably
near the northern border of the breeding range, two were recorded
on December 13.
The male in the present species has the two outermost primaries
decidedly attenuate, while in the female these two feathers are
normal. In addition, the back of the male is more rufescent than in
the opposite sex. An adult male, when first taken, had the base of
gonys pallid brownish drab; rest of bill, tarsus, and toes black;
iris Rood's brown.
LICHENOPS PERSPICILLATA PERSPICILLATA (Gmelin)
Motacilla perspicillata Gmelin, Syst. Nat., vol. 1, pt. 2, 1789, p. 969. (Rio
de la Plata.)
Specimens of the widely distributed silverbill were secured at the
following localities: San Vicente, Uruguay, January 27, 1921, adult
male; Las Palmas, Chaco, July 23, 1920, adult female; Resistencia,
Chaco, July 10, adult male; Berazategui, Buenos Aires, June 29;
Dolores, Buenos Aires, October 21, adult male and female; Ingeniero
White, Buenos Aires, December 13, immature male ; Tunuyan, Mendoza,
March 21, 1921, adult male, March 24 and 28, females; General
Roca, Rio Negro, November 30, 1920, adult male. Adult males
examined from the northern part of the Province of Buenos Aires
into Paraguay and southern Brazil have the white patch in the
wing at its maximum extent and may be considered as typical of
true perspicillata. The black on the outer webs of the primaries
extends only 2 or 3 mm. beyond the level of the primary coverts,
the median portions of the shafts of the ninth and tenth primaries
are white, and the dark distal tip is restricted. The white area
forms a prominent streak along the side of the closed wing. The
wing varies from 86.2 to 91.5 mm. (average of 12 specimens, 88.8
mm.). In skins from near Bahia Blanca, from the valley of the Rio
Negi-o, and from Mendoza the white wing patch becomes somewhat