NATURAL SCIENCES OP PHILADELPHIA. 483 



Ridgw., Pr. Boston Soc, May, 1873, 76. Sharpe, Cat. Ac. B. M., 

 1874, 75. 



CUmacocercus semitorquatus, Caban. J. f. Orn., 18G5, 407. 

 Falco brachypterus, Temra., PI. Col., I, 1824, pis. 116 (juv.), et 141 (adult). 

 Astur brachypterus, Spix, Av. Bras., I, 1824, 9. Vig. Zool. Jonrn., 

 I, 338. Stepb. Zool., XIII, pt. 2, 28. 



Nisus brachypterus, Less., Man. Orn., I, 1828, 98 ; Tr. Orn., 62. 

 Cav., Reg. An., ed. 2, I, 334. Schleg., Mus. Pays-Bas, Astures, 

 1862, 52. 



Accipiter brachypterus, Gray, List B. Brit. Mns., 69. 

 Micrastur brachypterus, Gray, Gen. B., ed. 2, 1841, 6; fol. 1849, 28, 

 sp. 1, pi. 10, f. 1 ; Hand List, I, 31, No. 290. Bonap. Consp., 1, 1850, 

 30. Pelz. Reis., Nov. Vog., 1865, 12 ; Orn. Bras., 1871, 7, 398. 

 Herpetotheres brachypterus, Kaup, Contr. Orn., 1850, 71. 

 Rhynchomegas brachypterus, Bonap., Rev. et Mag. Zool., 1854, 537. 

 "Falco leucomelas, Illig.," Lieut., Verz. Doubl., 1823, 62. 

 Garnifex naso, Less., L'Echo du Monde savant, annee 9, 1081 ; Rev. 

 Zool., 1842, 379. 



Falco per contator, Cabot, Journ. Bost. Soc., N. H., IV, 1844, 462. 

 Nigriblanco, Azara, Apunt, I, 1802, 124. 



Hab. The entire Intertropical Region (except Andean district), 

 north to Mazatlan (Pacific coast) and Vera Cruz (Atlantic coast), 

 and south to Paraguajr. Not yet recorded from the Andean dis- 

 trict south of New Granada, nor from western Amazonia. 



Sp. Char. Wing, 9.70-11.70 ; tail, 9.60-13.00 ; culmen, .80-1.00 ; 

 tarsus, 3.10-3.65 ; middle toe, 1.60-2.05. Third to sixth quill 

 longest; first much the shortest. Above plumbeous-black or 

 blackish-brown, interrupted by a more or less conspicuous nuchal 

 collar of white or ochraceous. Tail crossed by 4-7 narrow light 

 bands, usually interrupted. The last one terminal and the first 

 concealed. Adult : Lower parts entirely immaculate, the color 

 varying from pure white to deep ochraceous-buff; upper parts un- 

 variegated ; nuchal collar distinct. Young: Lower parts more 

 or less spotted or barred with blackish ; upper parts usually more 

 or less variegated with indistinct bars or transverse spots of 

 ochraceous or dull rusty ; nuchal collar more interrupted. "Iris 

 brown." 



Remarks. It is a noteworthy fact that all the specimens from 

 Costa Rica in the series we have examined are deep ochraceous be- 

 neath, while those from Mazatlan and Colima are pure white. 

 Whether this difference results from climatic causes, or merely 

 different stages of growth of the feathers, it is difficult to decide; 



