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272 BULLETIN 133, UNITED STATES NATIONAL MUSEUM
tion of brush. Their flight was rapid and tilting with the black
tail showing prominently as they darted away. The song is a
musical, even trill, resembling the syllables tree-ee-ee-ee-ee. On
November 24 I found a nest of this species, one of the prominent
structures made of sticks so abundant in the brush of this region.
The nest, placed in the top of a bush 3 feet from the ground, with-
out concealment, was an irregular ball, approximately 400 mm. in
outside diameter, constructed of thorny twigs from 100 to 300 mm.
long, ranging in size from fine sticks to those as large in diameter
as a lead pencil. A tubular entrance tunnel, made of small, very
thorny twigs, closely and firmly interlaced, led out at one side for a
distance of 400 mm., supported by a limb that grew out beneath the
nest. The nest ball was so compactly made that it required some
time and trouble to open it. The inner cavity was 125 mm. in
diameter and had in the bottom a firmly felted cup of plant down,
fur of the introduced hare (common in this region), and feathers.
Three eggs that lay on this soft bed, dull white in color, were on the
point of hatching and were badly broken in preparation. Two that
are more or less entire offer the following measurements, in milli-
meters: 20.9 by 15.1 and 20.1 by 14.5.
SIPTORNIS HUMICOLA (Kittlitz)
Synnalaxis humicola Kittlitz, Mem. Acad. Imp. Sci. St.- P6tersbourg, Div,
Sav., vol. 1, 1831, p. 185. (Valparaiso.),
Near Concon, Chile, where /Siptornis humicola was fairly common,
skins of two males were preserved on April 26 and 27 and a female
on April 28, 1921. The birds frequented dense thickets of low
brush that grew over the slopes of rolling hills, where they worked
slowly about among the limbs or occasionally on the ground, where it
was open but heavily protected above. In actions they suggested
Synallaxis f. frontalis. Usually they were silent and so were diffi-
cult to find, but on one encounter one burst out in a clear, trilled
song like that of some wren. The muscular part of the stomach in
this species is large and strong, heavier, in fact, in proportion to the
size of the bird than in some seed-eating finches.
A male, when first taken, had the maxilla and tip of the mandible
black; base of mandible gray number 8; tarsus, deep olive gray;
toes, tea green; iris, natal brown.
SIPTORNIS LILLOI Oustalet
Siptornis Lilloi, Oustalet, Bull. Mus. Hist. Nat. (Paris), vol. 10, 1904,
p. 44. (Lagunita, Tucuman.)
An immature female, shot at an altitude of 2,300 meters on the
Sierra San Xavier, above Tafi Viejo, Tucuman, was the only one
of these birds seen. The specimen is in the immature stage de-