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BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 257
LEPTASTHENURA AEGITHALOiDES AEGITHALOIDES (Kittlitz)
Synnalaxis Aegithalo'ides Kittlitz, Mem. Acad. Imp. Sci. St.-Petersbourg,
Div. Sav., vol. 1, 1831, p. 187. (Valparaiso.)
Near Concon, in the Intendencia of Valparaiso, Chile, where this
bird was fairly common from April 24 to 28, 1921, a male was secured
on April 24 and three females on April 24, 26, and 27. As
Kittlitz remarks that he secured his specimens " auf dem Hohen um
Valparaiso," these may be considered as topotypical specimens. The
present species is distinguished from L. platensis by somewhat more
bushy crest, darker coloration, and grayish white on the inner webs
of the rectrices. The genus Leptasthenura^ of which aegithalo'ides of
Kittlitz is the type, is distinguished among the Synallaxis group by
the possession of a long, slender gi'aduated tail of 12 rectrices and a
more or less developed crest. The head feathers in certain other
species are often full and long, but are kept closely appressed to the
head. In Leptasthenura the development of the crest is observed at
once when birds are handled in the flesh, though in the dried skin
it is sometimes difficult to distinguish.
Near Concon, L. aegithaJoldes was encountered, often in company
with other small brush-inhabiting birds, in open thickets of low
growth that covered the slopes of rolling hills, or in growths of
weeds and thorny shrubs near water. The birds clambered about
among the limbs, occasionally uttering low complaining notes, in
actions resembling titmice. They were gregarious and were not
seen alone. The long, slender tail was a prominent character that
served to identify them as they passed with tilting flight across
small openings between clumps of trees.
A female, taken April 24, had the maxilla and tip of the man-
dible dull black; base of mandible dusky green gray; iris natal
brown ; tarsus and toes dull black.
LEPTASTHENURA AEGITALOIDES PALLIDA Dabbene
Leptasthenura aegithalo'ides pallida Dabbene, El Hornero, vol. 2. no. 2,
January, 1921, p. 135. (Puesto Burro, Maiten. Chubut. alt. 700
meters.
)
The present form is similar to L. a. aegithalo'ides of Chile, but
is easily distinguished by its general paler coloration. On Decem-
ber 3, 1920, near General Roca, Rio Negro, I found two of these
birds resting in the sun in the tops of thick bushes in a region where
the atriplex and other growth typical of alkaline flats was tall and
dense. The birds rested quietly with long tails hanging straight
down, at intervals uttering a low buzzing trill very similar to the
songs of some Synallaxis. I was surprised to find that the bird
taken, secured during the act of singing, was a female. When fresh