FALCONID^ - THE FALCONS. 249 



oval, horizontal, with an exposed cartilaginous tubercle. Lores nearly naked, with scant 

 bristles. Wing long (much as in Buteo) ; the fourth or fifth quill longest, and the first 

 shorter than the eighth to the tenth ; outer four with inner webs sinuated. Tail long, 

 more than two thirds the wing; even or slightly rounded. Feet robust, when outstretched 

 reaching nearly to the end of the tail ; tarsus nearly twice the length of the middle, very 

 robust, the frontal and posterior rows of scutelte very distinct; outer toe longer than the 

 inner ; claws strong, well curved, and acute. Sexes alike ; young and old plumages very 

 different. 



This genus includes a- single species, tlie P. unicinctus, with its two climatic 

 races, unicvnctus of South America and harrisi of Middle America. It is 

 most nearly related to the genus Urubitinga, of tropical America, the species 

 of which are sluggish and almost Caracara-like in their habits, though they 

 are hardly more so than our own Buteones. The genus Craxirex of Gould 

 having been founded upon Butco galapagoensis, a species strictly congeneric 

 with £. horealis, it is necessary that a new generic name should be instituted 

 for the present species, since it so well merits separation to that rank. I 

 accordingly propose the name given at the head of this chapter. 



Species and Races. 

 P. unicinctus. Wing, 11.65 - 14.GU ; tail, 0.00 - 11.00 ; culmen, .82 - 1.10 ; 

 tarsus, 2.78 - 3.75 ; middle toe, 1.52 - 2.00. Adult. G-eneral color brownish- 

 black or blackish-brown, uniform, or slightly variegated by light spotting ; 

 the lesser wing-coverts and tibias deep rufous, or chestnut. Tail black ; the 

 end and base Avhite, as are also the tail-coverts. Young. Plumage greatly 

 variegated. Above blackish-brown, the feathers edged with I'usty; head 

 and neck streaked with pale ochraceous. Lower parts pale ochraceous or 

 yellowish-white, the breast and abdomen with longitudinal ovoid spots of 

 blackish; tibite with transverse bars of dark rusty; lower tail-coverts with 

 black shaft-streaks. Lesser wing-covert region only washed with rufous. 

 Tail grayish-brown, whitish at the tip, and crossed by narrow bands of 

 dusky. 



Adult with the blackish much broken up by lighter spotting. Wing, 

 11.65-14.60; tail, 9.00 - 10.50 : culmen, .82- 1.02 ; tarsus, 2.78-3.40; 

 middle toe, 1.52 - 1.85. Hab. South America . . \av. un icin ctus} 



1 Falco tcnicinctus, Temm. PI. Col. 313, 1820. Mojyhnus unicinctus, Less. Man. Orn. I, 1828, 

 90. Astur unicinctus, Cuv. Keg. An. (ed. 2), I, 1829, 332. — Strickl. Orn. Syn. I, 221.— 

 Kaup, Monog. Falc. 1850, p. 66. B^iteo unicinctus. Gray, List B. Brit. Mus. 18. — Ib. Hand 

 List, I, 7, No. 55. Nisus unicinctus, Less. Tr. Orn. p. 61. Hypomorphnus unicinctus, Tschudi, 

 Fauna Per. pp. 17, 85. Spizageranus unicinctus, Kaup, Ueb. Senck. 1845, 260. Urubitinga 

 %inicincta, Lafii. Eev. Zool. 1849, 99. — Pelz. Orn. Bras. I, 1868, 3, No. 10. — Ib. IV, 1871, 

 394. Polyhorus tceniurus, Tschudi, Av. Consp. Wiegm. Areli. 1844, 264. — Ib. Fauna Per. pi. 

 ii, Juv. It seems that the South American birds of this species never attain tlie .shnple tricolored 

 plumage assumed by the adult of the North American form, Temminck's figure (PI. Col. 313) 

 representing the nearest approach to it that I have seen, in a large series of adult specimens. 

 The following descriptions show the average adult of var. unicinctus : — 



Adult male (No. 13,908, Chile ; Lieutenant Gilliss). Eesenibling the immature of var. harrisi, 

 as described on p. 1569 (No. 56,763). Primaries edged terminally with whitish ; inner webs 

 of tail-feathers mottled whitish for their basal half, not showing the regular transverse bars seen 

 in the immature of var. harrisi : under suiface of primaries almost wholly white, becoming 

 a.shy, barred with dusky, towards their ends. Wing, 12.00 ; tail, 8.30 ; tarsus, 2.90 ; middle 



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