344 BULLETIN 5 0, UNITED STATES NATIONAL MUSEUM 



part (monogr.). — Peters and Griscom, Proc. New England Zool. Club, xi, 



1929, 44, part (crit.; Tehuantepee). 



Rupornis magnirostris griseocauda Bangs, Bull. Mus. Comp. Zool., Ixx, No. 4, 



1930, 190 (Tehuantepee). 



Buteo magnirostris petersi Brodkorb, Occ. Pap. Mus. Zool. Univ. INIichigan, No. 



425, 1940, 2 (above Arriaga, Chiapas, alt. 100 meters; crit.; orig. descr.). 

 Rupornis magnirostris suhsp. del Campo, Anal. Inst. Biol., xiii, 1942, 701 (Chiapas; 



Escuintla; .spec). 



BUTEO MAGNIROSTRIS GRACILIS (Ridgway) 



CozuMEL Insect Hawk 



Adult (sexes alike). — Similar to that of Buteo magnirostris griseo- 

 cauda, but decidedly smaller, and with the thighs and under wing 

 coverts wholly or nearly immaculate, instead of distinctly barred or 

 spotted; the breast vdih the lateral buffy margins of the feathers 

 wdder; the posterior underparts less washed with cinnamomeous. 



Juvenal (sexes alike). — Similar to that of Buteo magnirostris griseo- 

 cauda, but smaller, very slightly paler above; the spots on the feathers 

 of the upper abdomen not forming transverse bars; the thighs not 

 barred, only sparsely spotted with cinnamomeous. 



Natal down. — Not known. 



Adult male.—\\mg 200-205 (203); tail 143.8-150.5 (146.5); culmen 

 from cere 17-18 (17.6); tarsus 58.2-59.5 (58.8); middle toe without 

 claw 27.5-28.2 (27.9 mm.) (4 specimens). 



Adult female.— Wing 210-218 (216.2); tail 152.1-159 (153.9); 

 culmen from cere 17.7-19 (18.4); tarsus 58-60.8 (59.6); middle toe 

 without claw 29-30.7 (29.6 mm.) (5 specimens). 



Range. — Resident on the Islands of Cozumel, Meco, Holbox, and 

 probably on Mugeres Island, Yucatan. 



Type locality. — Cozumel Island, Yucatan. 



Aslurina ruficauda (not of Sclater and Salvin, 1869) Salvin, Ibis, 1885, 193 (Meco, 



Holbox, and Cozumel Islands); 1889, 374, part (Cozumel Island; crit.). — 



Salvin and Godman, Biol. Centr.-Amer., Aves, iii, 1900, 76, part (Cozumel 



Island). 

 Rupornis ruficauda Salvin and Godman, Biol. Centr.-Amer., Aves, iii, 1900, 



76, part. 

 Rupornis gracilis Ridgway, Proc. U. S. Nat. Mus., viii, 1885, 94 (Cozumel Island, 



off Yucatdn ; coll. U.S. Nat. Mus.).— Gurney, Cat. Birds Prey, 1894, 25.— 



Shakpe, Hand-list, i, 1899, 257. 

 Rupornis magnirostris gracilis Ridgway, Proc. U. S. Nat. Mus., viii, 1885, 578 



(Cozumel; full descr.; crit.). — Swann, Synopt. List Accip., pt. 2, 1919, 56; 



Synopsis Accip., ed. 2, 1922, 93, part (Cozumel); Monogr. Birds Prey, i, 



1930, 440 (monogr.).— Griscom, Amer. Mus. Nov., No. 236, 1926, 8 (Cozumel 



Island). — Peters and Griscom, Proc. New England Zool. Club, xi, 1929, 



45 (crit.; chars.; distr.). 

 Buteo magnircstris gracilis Peters, Check-list Birds of World, i, 1931, 237. — 



Brodkorb, Occ. Pap. Mus. Zool. Univ. Michigan, No. 425, 1940, 4 (spec; 



Cozumel Island). 



