POLTBOEUS.— MILVAGO. 127 



A good account of the nesting of this species in Mexico has been given by Grayson ^^ 

 and in Guatemala by Eobert Owen ^5. 



2. Polyborus pallidus. 



Polyborus audubonii (nee Cass.), Grayson, Pr. Boston Soc. Nat. Hist. xiv. p. 268 '. 



Polyborus tharus, var. audubonii (pt.) (nee Cass.), Lawr. Mem. Boston Soc. Nat. Hist. ii. p. 303 '. 



Polyborus cheriway pallidus, Nelson, Proc. Biol. Soc. Washington, xii. p. 8 ' ; N. Amer. Fauna, 



no. 14, p. 38 \ 

 Polyborus pallidus, Sharpe, Hand-l. Birds, i. p. 243°. 

 P. cheriway similis, vix minor, sed ubique pallidior (teste Nelson, I. c). 



Hob. Mexico, Tres Marias Is. {Grayson ^ ^, Nelson ^ *). 



Grayson was the first to record the presence of a Caracara on the Tres Marias 

 Islands ^, and the specimens he obtained were referred by Lawrence ^ to P. cheriway, 

 the species which inhabits the adjacent mainland of Central America. Mr. Nelson, 

 however, has drawn attention to the difierences exhibited by the insular form, and named 

 it P. cheriway pallidus. He says that the bird was abundant about the settlement on 

 Maria Madre, where the log-roads and dry bottoms of the canons were favourite resorts. 

 It was also found perched on tree-tops in the midst of unbroken forest, and was 

 commonly distributed over the other islands, including San Juanito. Iguanas were 

 very plentiful and formed the chief food, but the Caracaras readily devoured any carrion 

 obtainable *. 



MILVAGO. 



Milvago, Spix, Av. Bras. i. p. 12 (1824) ; Eidgw. Bull. U. S. Geol. & Geogr. Surv. i. p. 466 



(1878). 

 Ibycter, partim, Sharpe, Cat, Birds Brit. Mus. i. p. 34 (1874) . 



The genus Milvago is associated with Polyborus by Mr. Ridgway, its habits being 

 " chiefly terrestrial." The tarsus is much longer than the middle toe, but the outer 

 toe is decidedly longer than the inner; the posterior one does not reach the first joint 

 of the middle toe ; claws sharp, as in the Falcons ; posterior face of the tarsus with two 

 distinct rows of quadrate scales ; nostril circular, in the middle of the cere, its tubercle 

 exposed; anterior outline of the cere doubly curved; tooth and notch of the tomia of 

 the bill distinctly indicated ; lower jaw normally feathered. 



Two species are known: M. cUmango, inhabiting South America from Tierra del 

 Fuego to Buenos Ayres, and on the west to Peru ; and M. chimachima, extending 

 over Tropical America as far north as Panama. 



1. Milvago chimachima. 



Chimachima, Azara, Apunt. i. 50 '. 



Polyborus chimachima, Vieill. N. Diet. d'Hist. N. v. p. 259'. 



