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294 BULLETIN 133, UNITED STATES NATIONAL MUSEUM
marked degree the characters of large size and dark coloration that
distinguish the southern form.
XENOPSARIS ALBINUCHA (Burmeister)
Pachyrhamphus albinucha BuRMEasTER, Proc. Zool. Soc. London, 1868, p.
635. (Rio de la Plata, near Buenos Aires.)
Near Laguna Wall, 200 kilometers west of Puerto Pinasco, an
adult male was taken September 25, 1920, as it watched alertly for
insects from a low perch at the border of a thicket of vinal. The
bill in this specimen is decidedly larger than in a topotype of the
species examined in the collections of the United States National
Museum, and may perhaps represent a distinct form. The culmen
from the base measures 12.3 mm., while in the bird from Argentina it
is 10.4 mm. Difference between the two in heaviness of bill is no-
ticeable. A second specimen from Monteagudo, Tucuman, a male,
in the collection of the Museum of Comparative Zoology, agrees in
size with the bird from Buenos Aires (culmen from base 11 mm.).
CASIORNIS RUFA (Vieillot)
Thamnophilus rufus Vieillot, Nouv. Diet. Hist. Nat., vol. 3, 1816, p. 316.
(Paraguay.)
Near Las Palmas, Chaco, a female of this cotinga was shot July
13, 1920, and another, placed in alcohol, was taken July 21. Males
were secured at Kilometer 80, west of Puerto Pinasco, Paraguay,
September 11 and 16, and others were seen at Kilometer 25, September
1, and on the eastern bank of the Rio Paraguay, opposite Puerto
Pinasco, on September 30. The female from Las Palmas is deeper
rufous above than others examined. A specimen shot July 21 had
the tip of the bill dull black; base of mandible tilleul buff; base of
maxilla avellaneous ; iris natal brown ; tarsus and toes deep purplish
gray. Hellmayr '^^ considers C. fusca Sclater and Salvin, of which
I have seen only one skin, a race of rufa Vieillot.
A retiring species, the present form was found singly or in pairs
only in dense undergrowth in heavy woods, where it hopped about
from perch to perch or remained motionless among green leaves in
the pose of a flycatcher. The call note, heard rarely, resembled
tsa ah given in a high-pitched tone.
HABRURA PECTORALIS PECTORALIS (Vieillot)
Sylvia pectoralis Vieillot, Nouv. Diet. Hist. Nat., vol. 11, 1817, p. 210.
(Paraguay.)
An adult male secured at Las Palmas, Chaco, on July 17, 1920.
agrees in size and color with another taken (with an adult female)
«8Nov. Zool., vol. 15, June, 1908, p. 56.