FALC0:NID^ — THE FALCONS. 177 



exclusive of some of the West India Islands. North and south of the 

 Isthmus it is modified into geographical races, the southern of which is var. 

 tharus, MoL, and the northern var. auduhoni, Cass. 



The closely related genera Phalcobccnas, Milvago, Ihyder, and Daptrius 

 are peculiar to South America and the southern portion of Middle America, 

 most of tliem being represented by two or more species. They all form 

 a well-marked and peculiarly American group, for which I shall retain 

 Schlegel's term Polyhori. 



Their habits are quite different in many respects from those of other 

 Falconidce, for they combine in many respects the habits of the gallinaceous 

 birds and those of the Vultures. They are terrestrial, running and walking 

 gracefully, with the exception of the species of Ihyder and Daptrius, which 

 are more arboreal than the others, and are said also to feed chiefly upon 

 insects, instead of carrion. 



Species and Races. 



P. tharus. Wing, 14.50-17.70; tail, 10.00-11.00; culmen, 1.20-1.48; 

 tarsus, 3.20 - 4.20 ; middle toe, 1.75 - 2.30. 



Adult. Forehead, crown, occiput, back, rump, abdomen, sides, and 

 tibiae, and terminal zone of the tail, dull black. Neck, breast, tail- 

 coverts, and tail, dingy whitish. Interscapulars, breast, and tail with 

 transverse dusky bars. 



Young. Blackish areas replaced by dull brown ; region of the trans- 

 verse bars marked, instead, with longitudinal stripes. 



Adult. Whole body, with middle wing-coverts, variegated with 

 transverse bars of black and white ; tail-coverts barred. Terminal 

 zone of the tail about 2.00 wide. Young. Longitudinal stripes 

 over the whole head and body, except throat, cheeks, and tail- 

 coverts ; tail-coverts transversely barred. Hab. South America. 



var. tharus} 



^ Polyborus tharus. Falco tharus, Molina, Sp. Chil. p. 264, 343 ; 1782. Pohjborus tharus, 

 Strickl. Orn. Syn. I, 19, 1855. Falco cheriway, Jacq. Beytrag. p. 17, pi. iv, 1784. Pohjbo- 

 rus clieruvay, Rich. Schomb. Vers. Faun. Brit. Guiana, p. 741, 1840. Falco plancus, Gmel. 

 Syst. Nat. p. 257, 1789. Falco brasilicnsis, Gmel. Syst. Nat. p. 262, 1789 (et AucT.). 

 Polyborus brasiliensis, ViG. Zool. Jourii. I, 320, 1824. Ca.racara vulgaris, Less. Tr. Orn. p. 

 34 ; 1831. Polyborus vulgaris, Spix. Av. Bras. I, pi. i, a. . 



Adult male (21,850, South America; T. R. Peale). Forehead, crown, occiput, and wings 

 brownish-black ; middle wing-covei-ts fainter, with obscure whitish bars ; primaries white iii the 

 middle (just beyond the coverts), this portion having obsolete washes of grayish, in form of 

 faintly indicated transverse bars ; basal three-fourths of the tail white, with numerous narrow, 

 washed bars of grayish, these becoming more faint toward the base ; tail with a terminal zone of 

 black, about two inches broad. Cheeks, chin, and throat soiled white, unvaried ; body in general 

 {including neck, breast, sides, abdomen, back, and scapulars) transversely barred with black and 

 white, the white prevailing anteriorly ; beneath, the black bars grow gradually wider posteriorly, 

 giving the tibi<e and femorals a uinformly blackish appearance ; on the back and scapulars also 

 the black bars exceed the white in width, but they are very sharply defined, regular, and con- 

 tinuous ; rump, upper and lower tail-coverts, white, with numerous faint bars of grayish. Under 

 side of the wing black ; outer six primaries white in the middle portion, beyond the coverts, this 

 patch extending obliquely across ; secondaries rather broadly barred on basal two-thirds with 

 black and white, leaving the terminal third unvaried. Third quill longest ; fourth scarcely 



VOL. HI. 2.3 



