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264 BULLETIN 133, UNITED STATES NATIONAL MUSEUM
SIPTORNIS MALUROIDES (d'Orbigny and Lafresnaye)
Synallaxis maluroides cI'Orbigny and Lafresnaye, Mag. Zool., 1837, p. 22.
(Buenos Aires.)
S. maluroides is a bird of local distribution in the marshes of
Argentina and Uruguay, and extends north along the coast into
Eio Grande do Sul. It is often difficult to find and I met with it
personally at only three localities. On October 25, 1920, I found it
common in growths of rushes in the tidal marshes near the mouth
of the Rio Ajo, and collected two males and two females. Super-
ficially the birds resemble marsh wrens in appearance and in choice
of habit, and, save for their long tails, might easily be confused
with Cistothorus. Occasionally they were observed on the ground
searching for food near clumps of grass but more often were en-
countered only in the heavier growths of Juncus. When startled
they flew with tilting flight low over the grass, often blown about
in the stiff breeze that swept the marshes. In alighting they sometimes
perched for a short space with the head projecting above
the grass cover so that they were able to look about though their
bodies were entirely concealed. Like related species they were
usually frightened by the squeaking noise attractive to most small
oscinine birds and either flew to some safe retreat or hid in the
densest cover available. Females taken were about to lay. On a
second visit on November 15 I found these curious birds again
common and secured another specimen that was preserved as a
skeleton.
On February 7, 1921, an adult male maluroides was secured in
a fresh-water swamp in the valley of the Rio Cebollati, near
Lazcano, Uruguay. This bird was molting the feathers of wings and
tail. An immature male secured in the rushes of a cienaga near
Tunuyan, Mendoza, on March 26, is in full juvenal plumage.
Adults from Buenos Aires, when compared with the single specimen
from Uruguay, show no appreciable differences, though it is
possible that Uruguayan specimens may have larger bills. The
bird in immature plumage from Tunuyan has the anterior portion
of the crown slightly duller than dark olive buff, with only one or
two incoming feathers to suggest the rufescent crown of the adult.
The tail is also duller in color than in birds in full plumage.
Adult females have the crown patch slightly paler than males
though the distinction here is slight.
SIPTORNIS SULPHURIFERA (Burmeister)
Spnallaxis sulphurifera Burmeister, Proc. Zool. Soc. London, 1868, p.
636. (Buenos Aires.)
In the vicinity of the Rio Cebollati near Lazcano, Uruguay, the
present species was common from February 5 to 9, 1921, in marshes