Vol. XIII, pp. 25-31 May 29, 1899 



PROCEEDINGS 



BIOLOGICAL SOCIETY OF WASHINGTON 



DESCRIPTIONS OF NEW BIRDS FROM NORTHWESTERN 



MEXICO. 



BY E. W. NELSON. 



Tlie birds liere described were obtained during the past few 

 months by Mr. E. A. Goldman while making collections in west- 

 ern Mexico for the Bi'ological Survey of the U. S. De})artment of 

 Agriculture. A number of birds from southwestern Sonora show 

 closer relationship to forms peculiar to tlie Cape St. Lucas region 

 of Lower California than to races of the same species in south- 

 ern Arizona. This is well illustrated by several House Finches 

 from Alan:ios, Sonora, whicli are scarcely distinguishable from 

 typical Carpodacus mexiainus ruberrmnis from Lower California. 

 This interesting relationship between the birds of the mainland 

 and those of the peninsula is somewhat similar to that which 

 exists between certain species found near San Bias, Tepic, and 

 their rei)resentatives on the Tres Marias Islands. 



In addition to the birds named in the present paper, several 

 others have been described from Sonora, south of Guaymas. 

 These are Mr. Brewster's Pdltacnla cyanopyga 'pallida, Thryophibis 

 sinaloa cinereus, and Pollopt'da nigriceps restricla (Auk, VI, i)p. 

 85-98, 1889), and Callipepla gambeli fulvi'pectus Nelson (Auk, 

 XVI, pp. 26-27, 1899), all from Alamos. The result of the com- 

 paratively small amount of work on the birds of this region 

 seems to indicate the existence there of a minor faunal area of 

 comparativel}' limited extent. 



I am indebted to Mr. Robert Ridgway, curator, and Dr. Chas. 

 W. Richmond, assistant curator of birds, in the National Mu- 

 seum, for continued courtesies during the preparation of this 

 pajjcr. 



8— Hiiir.. Soc. Wash., Vni,. XIII. ibiU'.i (25) 



