Audubon's caeacaka — p. thai; us var. aududoxi. 371 



We are not yet in position to define the geographical distribution of 

 this variety with desirable precision. If, indeed, it were not diii'erent from 

 the well-known bird of South America, the task would be easy ; for it 

 would be said to inhabit all of South and Central America, Mexico, 

 parts of the West Indies, and thence to extend northward along the 

 southern border of the United States, from one side of the republic to 

 the other. But admitting a distinction, as recently claimed by Mr. Gassin 

 (ride Pr. Acad. Nat. Sc. Phila. Jan. 1865, p. 2), between the United States' 

 bird and that of regions more tropical, we have insufficient data for 

 determination of the line along which the two varieties inosculate, as 

 they certainly do somewhere, there being no considerable portions of 

 country, from the southern boundaries of the United States to Cape 

 Horn, where Caracaras are not to be found. 



On the other hand, the distribution within our limits of the Vulture- 

 eagle, or Eagle-vulture, has been accurately determined. Since its 

 introduction into our fauna bj' Audubon {vide Orn. Biog. ii, p. 350, 

 pi. 101, and B. Am. i, p. 21, pi. 1), who discovered it in Florida, it has 

 been shown to occur thence to the Pacific coast. Thus, Mr. Wurdemann 

 found it in Louisiana; Dr. Henry, in New Mexico; Dr. Heeruiann, iii 

 Arizona; Mr. Xantus, in Lower California ; while almost every naturalist 

 who has visited Texas has recorded its abundance in that State. Its 

 northward extension is thus seen to be strictly limited ; it may, in fact, 

 be taken as a type of several subtropical species which, though known 

 along onr southern frontier, never penetrate much over the border. 

 As a particular illustration of its general range, and in confirmation of 

 the remark just made, we may cite its distribution in Arizona alone. 

 There it is unknown in the northern, and even the central, mountainous 

 regions, where the climate is temperate, but is common in the valleys 

 of the G-ila and Lower Colorado, and iu the deserts of the southern por- 

 tions of the Territory at large. One of tlie authors above mentioned 

 has left us an interesting memorandum of his observations in this region. 

 " I am happy," he remarks, " to be able to add this interesting species 

 to the fauna of California, having seen it on the Colorado Eiver, near 

 Fort Tuma, in company with the Cathartes cmra. The carrion of an ox 



Circaetus hrasiUmsis, Cuv., Eegne Anim. 2d ed. i, 328. 



PohjUrus brasiUensis, Xia.. Zool. Journ. i, 1824, 320, 336; iii, 434.— Sw., Phil. Mag. i, 



1827, 3G6; Zool. 111. ser. ii, pi. 2; Classif. B. ii, iy:37, 209.— Bp., P. Z. S. v, lUd.— 



Dakw., Journ. Res. 64; Voy. Beag. iii, 9.— Bkidges, P. Z. S. xi, 108; Ann. N. 



H. xiii, 499.— Gj:ay, Gen. of B. ; and of many authors, not of the United States. 

 Polylorus vulgaris, Spix, A. B. i, pi. 1". — ViBiLL., Gal. Oia, i, 23, pi. 7.— KiXG, Voy. Beag. 



i,532.— ViG., Zool. Toy. Beech. 15, pi. 7.— Bp., Consp. Av. i, 1850, 13.— TsCHUDi, 



Wieg. Arch. 1844, 3. 

 Caraeara vulgaris. Less., Trait(5 d'Orn. 34. 

 Pandion caraeara, Griffith's Cuv. R. A. vi, 325. 



Hob. — South America. 

 PoLYEORDS THARUS var. AUDDBONi, {Cossin) Eidgwatj. 



" (?) Aqiiila maculosa, Vieill., Ois. Am. Sept." 



Polybonis vulgaris, AuD., Orn. Biog. ii, 1834, 350, pi. 161 (nee Spix). 



Polijborus brasiUensis, Bp., List, 1838, 2.— AuD., Syn. 1839, 4: B. Am. i, 1840 '^1 pi. 4. 



Po?i/Jor«s aacHs, Cass., 111. i, 1854, 113 ; Pr. A.N. 8.-18.55. 284; Baird's B. N. \ 1858 45 — 

 Beew., N. a. 0. i, 18.57, 58, pi. 11, figs. 18, 19.— Heerm., P. E. E. Rep. x, 1859, 

 31.— SCL., Ibis, i, 1859, 214 (Guatemala).— OwBX, Ibis, iii, 67 (eggs).- Guk.x., 

 Cat. Eapt. B. 1864, 17.— Dress., Ibis, 186.5, 329 (Texas). 



Polijhorus audnboni, Cass., Pr. A. N. S. 1865, 2.— Coues, iUd. 1866, 49 (Arizona).— L.vwi:., 

 Ann. Lye. N. Y. ix, 1868, 132 (Costa Eica) ; ibid, ix, 1869, 207 ( Yiicat.an).— Coop., 

 B. Cal. i, 1870, 492 (CaUfornia).— Eidgw., Pr. A. N. S. 1870, 145. 



Polylorus tliarus var. auduboni, Coues, Key, 1872, 220.- B. B. & E., N. A. B. iii, 1874, 178. 



-ffaJ.— Middle America. North to the southern border of the United States. Cubit 

 (Cab., J.f. 0.ji,lxxis; Gundl., Eepert. 1865, 221). (?) Trinidad (T.aylok, Ibis, 1864, 79). 



