NO. 1 6 THE FORMS OF THE BLACK HAWK-EAGLE — FRIEDMANN 3 



duras, British Honduras, Nicaragua, El Salvador, Costa Rica, and 

 Panama to Colombia, Ecuador, Peru, Venezuela, Trinidad, the 

 Guianas, northern and western Brazil (Para, the Amazon Valley, 

 Rio Purus, Rio Jurua and Mato Grosso) , to Bolivia (Santa Cruz) . 



The nominate form appears to be restricted to eastern Brazil 

 (Bahia, Espirito Santo, Minas Gerais, Rio de Janeiro, Santa Catha- 

 rina, and Sao Paulo) and possibly ranges to northeastern Argentina 

 (Misiones). The species has been recorded once from Paraguay 

 (Sapucai), but, in the absence of material from that country, it is 

 not possible to say which race may have been involved. 



Material examined. — Thanks to the cooperation of the authorities 

 of the Chicago Natural History Museum and the Museum of Com- 

 parative Zoology, I have been able to add to the material in Wash- 

 ington and have thus personally studied 30 specimens. In addition 

 to these, I am able to include here notes on a still larger number of 

 specimens in other museums, kindly made for me by Dr. Pinto on 

 the birds in the museum at Sao Paulo, Brazil ; by Mr. Peters on addi- 

 tional specimens in the Museum of Comparative Zoology, Cambridge ; 

 by Mr. Todd on those in the Carnegie Museum, Pittsburgh; by 

 Mr. deSchauensee on the birds in the Academy of Natural Sciences 

 of Philadelphia; and by Dr. Zimmer on those in the American Mu- 

 seum of Natural History, New York. The combined material may 

 be listed as follows : 



Spisaetus t. tyrannus. — Eastern and southeastern Brazil (Bahia 

 south to Sao Paulo) 20 (including the type) ; "South America" 2 ; 

 total 22 specimens. 



Spisaetus t. serus. — Mexico 8 ; Guatemala i ; British Honduras i ; 

 Honduras i ; Nicaragua i ; Costa Rica 4; Panama 10 (including the 

 type) ; Colombia 4 ; Venezuela i ; Dutch Guiana 6 ; Ecuador 2 ; north- 

 ern and western Brazil (Para, the Amazon Valley, Rio Purus and 

 Rio Jurua, Mato Grosso) 9 ; Bolivia 2 ; total 50 specimens. 



Remarks. — The two species of Spizaetus inhabiting the American 

 Tropics each divide into two races, but the geographic pattern of this 

 division is quite dissimilar in the two. In the case of the present 

 species the data, still incomplete for much of the interior of Brazil 

 (states of Maranhao, Ceara, Parahyba, Goyaz, southern Para, and 

 Mato Grosso), indicate that the nominate form is largely a bird 

 of the coastal or semicoastal forested areas from Bahia southward 

 to Sao Paulo, and that the species apparently does not occur in the 

 adjacent (to the west) extensive areas of "campos" country of the 

 "Planalto" and of the still farther inland grasslands stretching from 

 south of the Amazon forest to parts of northern and eastern Bolivia. 



