566 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



//. Throat with no browuishj no white nuchal collar. 



g. Upperparts dark slate-gray; wings and tail brownish. 



h. The dark bars progressively decreasing in width from the 

 upper abdomen toward the under tail coverts (s. Mexico to 



Nicaragua) M. ruflcollis guerilla, ad. d^ (p. 574) 



hh. The dark bars not narrower and not more widely spaced on 

 the under tail coverts and lower abdomen than on the 

 upper abdomen (Costa Rica to w. Ecuador). 



M. ruficollis interstes, ad. cf (p. 577) 

 gg. Upperparts brownish like the wings and tail. 



h. Tail with 3 white bands (not counting tips which are white). 

 i. Dark bars on thighs and under tail coverts narrower and 

 more widely spaced than those on the upper abdomen (a. 

 Mexico|to|Nicaragua) . 



M. ruflcollis guerilla, ad. ? (p. 574) 

 a. Dark bars on thighs and under tail coverts not narrower 

 and not more widely spaced than those on upper abdomen 

 (Costa Rica to w. Ecuador). 



M. ruflcollis interstes, ad. 9 (p. 577) 

 hh. Tail with at least 4 white bands exclusive of the white tips. 

 Underparts heavily barred, at least on breast and upper 

 abdomen: 



(Costa Rica to w. Ecuador). 



M. ruflcollis interstes, juv. (p. 577) 

 (S. Mexico to Nicaragua) 



M. ruflcollis guerilla, juv. (p. 575) 

 ce. Underparts immaculate or only sparsely barred: 

 (Costa Rica to w. Ecuador). 



M. ruflcollis interstes, juv., plain phase (p. 575) 

 (S. Mexico to Nicaragua). 



M. ruflcollis guerilla, juv., plain phase (p. 577) 



357 (Montana Sierra, Valle, and Chacna, 200-300 m., and Limoues, 700 m.^ 

 Venezuela).' — Micrastur zonothorax Sclater and Salvin, Proc. Zool. Soc. London, 

 1869, 252, 254 (coast range of Puerto Cabello, Venezuela; crit.), 366 (monogr.); 

 1873, 511 (Venezuela); Nom. Av. Neotr., 1873, 120; Sharpe, Cat. Birds Brit. 

 Mus., i, 1874, 79 (Colombia; Venezuela); Ridgway, Proc. Acad. Nat. Sci. Phil- 

 adelphia, 1875, 489 (monogr.); Ibis, 1876, 3 (diagnosis); Gurney, List Diurn. 

 Birds Prey, 1884, 25, 120, in text (crit.); Cat. Birds Prey, 1894, 19; Bradbourne 

 and Chubb, Birds South Amer., i, 1912, 64 (Venezuela; Colombia). — Todd and 

 Carriker, Ann. Carnegie Mus., xiv, 1922, 158 (Cincinnati, Sierra Nevada at 8,000 

 feet. Las Vegas, San Lorenzo, Pueblo Viejo, and Chirua, Santa Marta, Colombia; 

 crit.). — Micrastur ruficollis zonothorax Swann, Synopt. List Accip, pt. 1, 1919, 

 16; Peters, Check-list Birds of World, i, 1931, 27S.— Micrastur guerilla zonothorax 

 Chapman, Bull. Amer. Mus. Nat. Hist., xxxvi, 1917, 241, in text; Hellmayr, 

 Nov. Zool., xxviii, 1921, 179 (crit.; range). — Micrastur ruficollis (not Sparvius 

 ruficollis Vieillot) Ridgway, Proc. Boston Soc. Nat. Hist., xvi, 1873, 78, part (in 

 synonymy). — Climacoccrcus zonothorax Swann, Synopt. List Accip., 1919, subst. 

 p. 16; Synop. Accip., 1, 1921, 26. — Clamosocircus zonothorax Swann, Monogr. 

 Birds Prey, i, 1925, 147 (monogr.). 



