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, Elanus , and their affines, as shown on page 147. 
ELANOIDES FOKFICATUS. 
Falco forficatus Linn. S. N. i, 1758, 89. 
Nauclerus forficatus Ridgw. Pr. Phil. Ac. Pec. 1870, 144; Pr. Boston Soc. N. H. 
May, lb/3, 52; Am. Nat. vii, April, 1873, p —; B. B. & JR. Hist. N. Am. B. iii, 
1874, 192. 
Falco furcatus Linn. S. N. i, 1766,129.— Gm. S. N. i, 1788, 262.— Latham, Ind. Orn. i, 
1/90, 22.— Shaw & Nodd. Nat. Miec. 1795, pi. 204.— Daud. Tr. ii, 1800, 152.— 
Shaw, Zool. vii, 1812, 107.— Wils. Am. Orn. vi, 1812, 70, pi. 51, figs. 1, 3.— 
Bonap. Ann. N. Y. Lyc. ii, 1828, 31; Isis, 1832, 1138.—Aur>. B. Am. 1831, pi. 72 ; 
Orn. Biog. i, 1831, 368; y, 371.— Schl. u. susem. Yog. Eur. 1839, taf. 32, f. 1. 
M ilvus furcatus Vieill. O. Am. S. 1807, pi. x. 
Elanoides furcatus V ieill. Enc. Metli. iii, 1823,1205.— Gray, List. Acc. B.M. 1844, 44. 
—Strickl. Orn. Syn. i, 1855, 141.— Scl. & Salv. Ibis, 1859, 220; Norn. Neotr. 
1873, 121.— Owen, Ibis, 1860, 240.— Sciil. Mus. P.-B. Milvi, 1862, 5.— Sharpe, 
Cat. Acc. B. M. 1874, 317. 
Elan us furcatus \ ig. Zool. Journ. i, 1824, 340.— Stepii. Zool. xiii, 1826,49, pi. ii.—Cuv. 
Reg. An. ed. 2, i, 1829, 334.— James, ed. Wils. Am. Orn. i, 1831, 75.— Jard. ed. 
Wils. ii, 1832, 275.— Nutt. Man. 1833, 94. 
Nauclerus furcatus Vnl Zool. Journ. ii, 1825, 387 ; Isis, 1830, 1043.— Less. Man. i, 
1828, 101 ; Trait6, 1831, 73.— Swains. Classif. i, 1837, 312; ii, 210.— Gould, B. 
Eur. 1837, pi. xxx.— Bonap. Comp. List, 1838, 4; Cat. Ucc. Eur. 1842,20 ; Consp. 
b lfc ’ 50 > 21.— Aud. B. Am. fol. 1839, pi. 72; oct. ed. 1839, i, 78, pi. 18; synop. 1839, 
14.—R. Schomb. Reis. Br. Guian. 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. Oblogy, i, 1857, 38.— 
W oodh. Expl. Zuni, 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, J865,325.— Coues, Pr. Phil. Acad. 1866, p. —; Key N. Am. B. 1872, 
211; Cheek 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. 
Elanoides yetapa Vieill. Enc. Mdth. iii, 1823, 1205. 
Falco yetapa Max. Beitr. iii, Abth. i, 1830, 141. 
Accipiter cauda furcata Catesby, N. H. Carol, i, 1754, pi. iv. 
Accipiter milvus carolinensis Briss. Orn. i, 1760, 418. 
The Swallow-tailed Hawk Catesby, Carol, i, 1731, 4, pi. 4. 
Le Milan de la Caroline Briss. Orn. i, 1760, 418. 
Swallow-tailed Falcon Latham, Synop. i, 1781, 60.— Pennant, Arc. Zool. ii, 1785, 210, 
No. 108, pi. x. 
Hab.—The whole of tropical and subtropical America, south to Para¬ 
guay, Buenos xYyres, 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 baud across the rump pure white. Back, wings, and tail plain pol¬ 
ished blackish, with varying reflections; tertials white, with blackish 
tips. 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 reflection incertain lights. 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 
