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

282 BULXJETIN 133, UNITED STATES NATIONAL MUSEUM
taken by the Page expedition at Parana. The type-locality was sub-
sequently designated as Catamarca. Two immature specimens (fully
grown) that I secured April 17, 1921, on the lower slopes of the
Sierra San Xavier, above Tafi Viejo, Tucuman, are distinctly more
yellowish olive both above and below than specimens from the
Chaco, Parana (the Page specimens), and Uruguay, and indicate
that there are two forms of the bird under discussion in Argentina,
It is assumed that the Tucuman specimens are similar to those from
Catamarca so that they are given the name oleaginus. The somewhat
duller-colored bird from farther east must take the name
acritus (Oberholser) described from Sapucay, Paraguay.
On the loAver forested slopes of the Cumbre above Tafi Viejo these
birds were fairly common in dense growths of bushes and herbaceous
vegetation, but worked about under the cover of large nettlelike
plants where it was difficult to secure them.
XENICOPSIS RUFO-SUPERCILIATUS ACRITUS (Oberholser)
. Anal)a::enops acritus Oberholser, Proc. Biol. Soc. Washington, vol. 14,
Dec. 12, 1901, p. 187. (Sapucay, Paraguay.)
The type of X. r. acritus is an immature bird in the somewhat
brighter more yellowish olivaceous plumage that distinguishes immature
from adult individuals in this species, a fact that seems
to have led to its separation originally. With oleagitius restricted
to a more western range in Catamarca and Tucuman (probably
north into Bolivia), the name acritus becomes available for the
form of northeastern Argentina and Paraguay, distinguished from
oleaginus by duller more grayish coloration. Typical X. r. rufo-
superciliatus is brighter, more rufescent on the dorsal surface,
especially on the wings and has the markings on the under surface
somewhat less sharply defined.
An adult male taken at Las Palmas, Chaco, on July 21. 1920, was
the only one seen until I reached Lazcano, Uruguay, where two
were seen and an immature female Avas taken near the Rio Cebol-
lati on February 8. At Kio Negro, Uruguay, where the birds
were fairly common from February 15 to 18, an immature male
was preserved February IT, and a female of the same age on
February 18. The adult male from Las Palmas, in full winter
plumage, though a trifle brighter than two specimens from the
Page expedition, is duller colored than the type of the subspecies.
Two from Rio Negro, Uruguay, resemble the type save that they
have not quite completed the molt into full plumage. The one from
Lazcano in the same stage of molt is darker.
These birds were found in dense thickets, usually in lowlands,
wliere it was more or less wet and swampy. They worked do-