181 



pared closely, the two are found to possess no real affinities of structure. 

 The same is true of its relation to Nauclerus riocouri, usually placed in 

 the same genus; the latter being very much more intimately related to 

 the genera Ictinia, Ulanus, and their affines, as shown on page 147. 



ela:s^oides forficatus. 



FalcoforficatusLiSN. S. N. i, 1758, 89. 



Nauclerus forficatus Eidgw. Pr. Phil. Ac. Dec. 1870, 144 ; Pr. Boston Soc. N. H. 



May, 1873, 52; Am. Nat. vii, April, 1873, p — ; B. B. & K. Hist. N. Am. B. iii, 



1874, 192. 

 Falco furcatus Linn. S. N. i, 1766, 129.— Gm. S. N. i, 1788, 262.— Latham, lud. Orn. i, 



1790, 22.— SiiAW & NoDD. Nat. Misc. 1795, pi. 204.— Daud. Tr. ii, 1800, 152.— 



SiiAW, Zool. vii, 1812, 107.— WiLS. Am. Orn. vi, 1612, 70, pi. 51, tigs. 1, 3.— 



BoNAP. Aun. N. Y. Lvc. ii, 1828, 31; Isis, 1832, 1138.- AUD. B. Am. 1831, pi. 72 ; 



Orn. Biog. i, 1831, 368; v, 371.— Schl. u. susem. Viig. Eur. 1839, taf. 32, f. 1. 

 AliJvus furcatus ViEirx. 0. Am. S. 1807, pi. x. 

 Elanoides furcatus YiVAiA.. Euc. Meth. iii, 1823, 1205.— Gkay, List. Ace. B.M. 1844, 44. 



— Steickl. Oru. Syn. i, 18.55, 141.— Scl. & Salv. Ibis, 18.59, 220; Norn. Neotr. 



1873, 121.— Owen, Ibis, 1860, 240.— Schl. Mus. P.-B. Milvi, 1862, 5.— Sharpe, 



Cat. Ace. B. M. 1874, 317. 

 Elamisfurcatus YiG. Zool. Journ.i, 1824, 340.— Steph. Zool. xiii, 1826,49, pl.ii.— Cuv. 



Eeg. An. ed. 2, i, 1829, 334. — James, ed. Wila. Am. Orn. i, 1831, 75. — Jard. ed. 



Wils. ii, 1832, 275.— NUTT. Man. 1833, 94. 

 Nauclerus furcatus ViG. Zool. Jonrn. ii, 1825, 387 ; Isis, 1830, 1043.— Less. Man. i, 



1828, 101 ; Traite, 1831, 73.— Swains. Classif. i, 1837, 312; ii, 210.— Gould, B. 



Eur. 1837, pi. xxx. — Bonap. Conip. List, 1838, 4 ; Cat. Ucc. Eur. 1842, 20 ; Cousp. 



i, 1850, 21.— AuD. B. Am. fol. 1839, pi. 72; oct. ed. 1839, i, 78, pi. 18 ; synop. 1839, 



14.— R. SCHOMB. Eels. Br. Guiau. 1840, 735.— De Kay, Zool. N. Y. ii. 1844, 12, 



pi. vii, f. 15.— Gray, Gen. i, 1845, 25, pi. 9, fig. 9 ; Gen. & Subgen. B. M. 1855, 



6;' Hand List, i, 1869, 27.— Hartl. Ind. Azara, 1847, 57.— Kaup, Contr. Orn. 



1850, 57.— Brewer, ed. Wils. Synop. 1852, 685; N. Am. Oology, i, 1857, 38.— 



WooDH. Expl. Zuui, 1853, 60.— Burm. Th. Bras, ii, 1856, 110.— Cass. B. N. Am. 



1858, 36.— Baird, Cat. N. Am. B. 1859, No. 34.— Taylor, Ibis, iv, 1862, 128.— 



Dresser, Ibis, 1865, 325. — Coues, Pr. Phil. Acad. 1866, p. — ; Key N. Am. B. 1872, 



211; Check List N. Am. B. 18/3, 67; Birds Northwest, 1874, 332.— Leot. Ois. 



Triuid. 1866, 30.— Gundl. J. f. O. 1871, 370.— Newt. ed. Yarr. Br. B. 1871, 



103.— Pelz. Orn. Bras. 1871, 6, 398. 

 Elanokles yetapa Vieill. Enc. Meth. iii, 1823, 1205. 

 Falco yetapa Max. Beitr. iii, Abth, i, 1830, 141. 

 Accipiter cauda furcata Catesby, N. H. Carol, i, 1754, pi, iv. 

 Accipittr milvus carolinensis Briss. Orn. i, 1760, 418. 

 The Swallow-tailed Hawk Catesby, Carol, i, 1731, 4, pi. 4. 

 Le Milan de la Uaroliue Briss. Orn. i, 1T60, 418. 

 Swallow-tailed Falcon Lathaji, Synop. i, 1781, 60. — Pennant, Arc. Zool. ii, 1785, 210, 



No. 108, pi. X. 



Sal). — The whole of tropical and subtropical America, south to Para- 

 guay, Bueuos Ayres, and Chile, north in the interior districts of the 

 United States to Minnesota and Wisconsin, and in the Atlantic States 

 to Pennsylvania. Accidental in the British islands (Nat. Mus.!); 

 Minnesota, 30 miles north of Mille Lac, lat. 47° (Trippe, Pr. Essex 

 Inst., vi, 1871, 113), 



Wing, 15.40-17.70; tail, 12.50-14.50; culmen, 0.70-0.80; tarsus, 1.00 

 -1.30; middle toe, 1.00-1.20. Head, neck, entire lower parts (includ- 

 ing lining of the wing and basal half of the secondaries underneath), 

 and band across the rump pure white. Back, wings, and tail plain pol- 

 islied bhK'kish, with varying retlections ; tertials white, with blackish 

 tii)S. Adult : — The white of the head and neck immaculate ; back scapu- 

 lars and lesser wing-coverts with a soft reflection of dark purplish 

 bronze, the other black portions with a glaucous or chalky cast, with a 

 green retiection in(;ertain liglits. Young : — Feathers of the head and neck 

 with dusky shaft-streaks; the black above less glossy, more brownish, 

 the bottle-green reflection replacing the soft purplish bronze on the 



