Vol. 5, p. 145. January 30, 1925. 



Occasional Papers 



OF THE 



Boston Society of Natural History. 



A NEW GEOSITTA FROM WESTERN ARGENTINA. 



BY JAMES L. PETERS 



Soon after I had listed a Geositta taken by me in northern 

 Patagonia (Bull. Mus. Comp. Zool., vol. 65, p. 312, May, 1923) as 

 Geositta cunicularia cunicularia (Vieillot), I became convinced 

 that in reality it represented a new form. In the spring of 1924 

 I had the opportunity of showing the specimens to Dr. C. E. 

 Hellmayr, who compared them critically with all the related 

 forms, and pronounced my bird to be undescribed. I therefore 

 take pleasure in naming it 



Geositta cunicularia hellmayri, subsp. nov. 



Type, adult male, No. 85339 Museum of Comparative Zoology, from 

 Huanuluan, Argentina; collected September 25, 1920, by J. L. Peters. 



Characters. — Similar to Geositta cunicularia cunicularia of eastern Argentina, 

 but largei and paler above and with the light bases of intermediate series of 

 upper tail-coverts of greater extent and forming a poorly defined bar or patch . 



Measurements. — Type and Topotypes: Adult Male (seven specimens), 

 wing, 97.5 mm. (93 to 101); tail-feathers, 53 (51 to 54); tarsus, 21.5 (21 to 23); 

 culmen to base of forehead, 21 (20 to 22). Adult Female (four specimens), 

 wing, 94 (88 to 97) ; tail-feathers, 51 (48 to 53) ; tarsus, 21 (20 to 22) ; culmen to 

 base of forehead, 20 (19 to 21). 



Range. — Western Rio Negro Province and probably most of 

 arid western Argentina. 



Compared with Geositta c. fissirostris of central Chili it is simi- 

 lar and about intermediate between that form and G. c. frobeni 

 of northwestern Argentina, Bolivia and northwestern Peru; 

 nearest to the latter and agreeing with it in size, in coloration of 

 upper tail-coverts and in reduction of the dusky spotting on the 

 chest, but differing in much paler, sandy-grayish brown, instead 

 of earthy-brown upper parts. 



From G. c. fissirostris it differs in larger size, almost creamy- 

 white upper tail-coverts, less well-developed pectoral spotting 

 and paler basal portion of tail. 



