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

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240 BULLETIN 133, UNITED STATES NATIONAL. MUSEUM
tail against a tree trunk, with wings spread, mouth open, and crest
raised.
It was recorded west to Kilometer 110, west of Puerto Pinasco.
CAMPYLORHAMPHUS RUFODORSALIS (Chapman)
Xiphorhynchus rnfodorsalis Chapman, Bull. Amer. Mus. Nat. Hist., voL
2, July 5, 1889, p. 160. (Conimba, Matto Grosso, Brazil.)
An adult male taken at Las Palmas, Chaco, July 19, 1920, and a
female from the Riacho Pilaga, Formosa, secured August 11, are
referred to the present species. Menegaux and Hellmayr ^'^ consider
rnfodorsalis indistinguishable from lafresnayanus (d'Orbigny) from
Bolivia on the basis of examination of a series from Mattogrosso,
d'Orbigny's original specimens marked Chiquitos, and a skin from
Rio de la Plata. Through the kindness of W. E. Clyde Todd, I
have seen five skins from the collections of the Carnegie Museum
from Bolivia, three from Guanacos, Province of Cordillera, one from
Palmarito, Rio San Julian, Chiquitos, and one from Curiche Rio
Grande, eastern Bolivia. These differ constantly from the Argentine
specimens in shorter, more slender bill (culmen from base, 67-73.5
mm.), and in duller, less rufescent coloration on the ventral surface,
so that on the basis of this material I must hold rnfodorsalis valid.
The two skins from Chaco and Formosa have the culmen from base
90 and 87.8 mm., respectively. A third specimen from the Rio
Bermejo (Page expedition), with the ends of both mandibles shot
has the base of the bill much heavier than is true in the
Bolivian birds. The three Argentine skins agree in being more
rufescent below than the others. They are listed here under a spe-
cific name, though it is probable that i^fodorsalis will prove to be
a geographic race of lafresnayanus.
This curious form was encountered in low, swampy lands in heavy
growths of timber, where it frequented dense cover. The birds
clambered alertly up sloping tree trunks, with the tail braced to aid
their ascent, and at any alarm disappeared in the jungle. From
their actions I judged that the grotesque curved bill was employed
to search for insects among the stiffened leaves of bromeliaceous
epiphytes that grew abundantly on trees and shrubs; the clasping
stems of the leaves of these plants formed cups that harbored con-
siderable animal life, and often contained considerable water in
which unfortunate insects were drowned, a feeding ground inacces-
sible save to the curious beak of this wood hewer.
A male, taken July 19, had the bill orange cinnamon, shaded with
fuscous at tip and base of culmen; iris deep-brownish drab; tarsus
and toes deep olive ; underside of toes shaded with yellowish.
'8 Mem. Soc. Hist. Nat. Autun, vol. 19, 1906, pp. 78-79.