564 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



//. Dorsal coloration darker, fuscous-black to black (Mexico ton. South 



America) M. semitorquatus naso, juv. (p. 568) 



dd. Breast solid white or solid black or brownish black, the rest of the 

 underparts barred with brownish black. 

 e. Underparts solid black or dark brownish black. 

 f. Underparts dark brownish black (Mexico to n. South America). 

 M. semitorquatus naso, melanistic phase (p. 568) 

 //. Underparts deep black. 



M. semitorquatus buckleyi, melanistic phase (extralimital) 

 ee. Underparts immaculate white or buff. 



A Light bands of the tail feathers with brown patches in their 

 centers; size small, wing under 230 mm. 



M. semitorquatus buckleyi, ad. (extralimital) . 



//. Light bands of the tail feathers with no brown patches in them; 



size larger, wings over 230 mm. 



g. Size larger, wings of male usually over 265 mm. in length; of 



females usually over 275 mm. (Mexico to n. South America). 



M. semitorquatus naso, ad. (p. 567) 



gg. Size smaller, wings of males usually under 265 mm. in length; 



of females usually under 275 mm. 



M. semitorquatus semitorquatus, ad. (extralimital) 

 aa. Size smaller, wing under 200 mm. in length. 



b. Tail with only 1 white band M. plumbeus (extralimital) ^^ 



bb. Tail with 2 or more white bands. 



c. Throat and breast tawny-cinnamon to tawny-chestnut. 



M. ruficollis ruficollis (extralimital) ^^ 



*' (?) Micrastur guerilla (not of Cassin) Berlepsch and Taczanowski, Proc. Zool- 

 Soc. London, 1883, 574 (Chimbo, nw. Ecuador); 1884, 310 (Suruputa, w. Ecuador; 

 crit.). — Micrastur plumbeus Sclater, Bull. Brit. Orn. Club, xxxviii. No. 231, 1918, 

 44 (Carondelet, Rio Bogota, Esmeraldas, nw. Ecuador; coll. Brit. Mus.); Chap- 

 man, Bull. Amer. Mus. Nat. Hist., Iv, 1926, 222; Peters, Check-list Birds of 

 World, i, 1931, 278. — Climacocercus plumbeus Swann, Synopt. List Accip., pt. 

 3, 1920, 115; Synop. Accip., pt. 1, 1921, 26 (nw. Ecuador). — Clamosocircus, 

 plumbeus Swann, Monogr. Birds Prey, i, 1925, 150 (monogr.). 



8° Sparvius ruficollis Vieillot, Nouv. Diet. Hist. Nat., x, 1817, 322, 323 (South 

 America); Encycl. Meth., iii, 1823, 1263, 1264; Pucheran, Rev. Mag. Zool., ii, 

 1850, 91 (crit. on type spec). — Micrastur ruficollis Strickland, Orn. Syn., i, 1855, 

 122; Sclater and Salvin, Proc. Zool. Soc. London, 1869, 366 (monogr.); Nom. Av. 

 Neotr., 1873, 120; Ridgway, Proc. Boston Soc. Nat. Hist., xvi, 1873, 78, part 

 (monogr.; Brazil); Proc. Acad. Nat. Sci. Philadelphia, 1875, 490, part (monogr.; 

 excl. "plumbeus phase" = M. gilvicollis) ; Ibis, 1876, 3 (diagnosis); Sharpe, Cat. 

 Birds Brit. Mus., i, 1874, 76, 456 (Bahia, Brazil); Gurney, List Diurn. Birds 

 Prey, 1884, 25, 119 (crit.); Cat. Birds Prey, 1894, 19; Salvadori, Boll. Mus. Zool. 

 Torino, xii, 1897, 29 (San Lorenzo, n. Argentina; descr. young; crit.); Ihering, 

 Rev. Mus. Paulista, iii, 1899, 346 (Piquete, Sao Paulo, s. Brazil); vi, 1904, 337 

 (Paraguay); Hellmayr, Abh. Bayer Akad. Wiss., Kl. II, xxii, pt. 3, 1905 (1906), 

 573 (crit. on Falco xanthothorax Spix); Nov. Zool., xxviii, 1921, 179 (crit.; range); 

 Dabbene, Bol. Soc. Physis Buenos Aires, i, 1914, 299 (San Lorenzo, Jujuy, Argen- 

 tina; Sapucay, Paraguay). — Micrastur ruficollis ruficollis Swann, Synopt. List 

 Accip., pt. 1, 1919, 15 (e. South America); Peters, Check-list Birds of World, i, 

 1931, 277. — Climacocercus ruficollis Cabanis, Journ. fiir Orn., 1865, 407; Swann, 



