PROCEEDINGS OP THE ACADEMY OP 



January 31st. 

 The President, Dr. Bridges, in the Chair, 

 members present. 



On report of the respective Committees, the following papers were 

 ordered to be published : 



Notes on some new and little known Eapacions BIRDS. 

 BY JOHN CASSIN. 



1. Polyborus Audubosii, nobis. 



Polyborus vulgaris (Vieill.), Aud., Orn. Biog., ii. p. 350 (1834). 

 Polyborus brasiliensis (Gm.), Aud., B. of Am., Oct. ed. i. p. 21 (1840). 

 Polyborus tharus (Mol.), Cass., B. of Cal. and Texas, i. p. 113. 

 Aud., B. of Am., pi. 161 ; Oct. ed., i. pi. 4. 



Back and rump brownish black in all ages and stages of plumage, (not 

 transversely banded as in P. tharus.) Under tail coverts white, nearly pure, 

 or with a few indistinct traces of dark transverse bands on the longer fea- 

 thers. In all other respects very similar to P. tharus of Chili and other coun- 

 tries on the Pacific coast of South America. In P. tharus the back and rump 

 are transversely banded with brownish black and white, in all ages, and the 

 under tail coverts are white, with well defined transverse narrow bands of 

 dark brown. In size, the present bird seems to be rather the larger. 



The specimen now described is Mr. Audubon's type from Florida, presented 

 by him to this Academy, and is very accurately given in the plates above 

 cited, the upper figures in which represent the black upper parts as above 

 described. In his descriptions, he says " cere carmine" which color is also 

 given in his plates ; but in the South American species, seen in abundance 

 in Patagonia by Dr. Charles Pickering, during the voyage of the United 

 States Exploring Expedition in the Vincennes and Peacock, that distin- 

 guished naturalist says explicitly, " The skin about the bill has not the bright 

 red color as given in Mr. Audubon's figure from a Florida specimen." (Mamm. 

 and Orn. U. S. Expl. Exp., p. 100.) This difference in the color of the cere 

 may be characteristic, though more probably, in my opinion, it is dependent 

 on season only, the brighter or red color being that accompanying the more 

 mature or nuptial plumage, which is the case in the Rasorial or Gallinaceous 

 birds, and analogous groups throughout the circle of Birds. Numerous spe- 

 cimens of this species, from Texas and Mexico, are in the collection of the 

 Smithsonian Institution. 



2. SriLORNis Bacha, (Daudin.) 



Falco Bacha, Baud., Traite" d'Orn., ii. p. 43 (1800). 



Spilornis Bacha, (Daud.) Cass., Proc. Acad. Philada., 1859, p. 31. 



Le Vaill., Ois. d'Afr., i. pi. 5. 



In a Catalogue of birds collected by Mr. DuChaillu in the countries on the 

 Gamma and Ogobai Rivers, Western Africa, printed in the Proceedings of the 

 Academy, as above cited, I applied the name Spilornis Bacha to a species, one 

 specimen of which was in that collection and is now in the Academy Museum. 

 This specimen is evidently that of a young bird bearing little resemblance in 

 colors to the adult, and I have seen no other of the same species from West- 

 ern Africa. In the statement in the Catalogue alluded to, that this species is 

 "quite identical with the Bacha of Southern Africa, of which a very com- 

 plete series is in the Academy Museum," I may have been mistaken in relying 

 on such specimens as being from that continent. I do not know, however, 

 ihat such is certainly the case ; the specimen now before me from Western 

 Africa so nearly resembling other young birds in the Academy Museum, un- 



[Jan. 



