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 

 . away, 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. 



