26 Field Museum of Natural History — Zoology, Vol. XIII. 

 *Otus choliba crucigems" {Spix). Spix's Screech Owl. 



Strix crucigera Spix, Av. Bras., I, 1824, p. 22, pi. 9 (Amazon River Region). 

 Pisorhina choliba crucigera Hellmayr, Nov. Zool., XIII, 1906, p. 45; lb. Abh. 



K. Bayer, Akad. Wiss., Miinchen, II, 1906, p. 575. 

 Otus choliba crucegera Hellmayr and Seilern, Archiv. fur Naturg., Ab. A. 



Heft 5, p. 158. 

 Otus roraimae Salvin, Bull. Brit. Om. Club, VI, 1897, p. 38. 

 Otus crucigerus Chubb, Bds. Brit. Guiana, I, 1916, p. 287. 



Range: Northern Brazil, East Peru, Guiana, Trinidad, Venezuela, 

 Colombia, Panama, and Costa Rica. 



9 : Colombia 4 ; Venezuela 3 ; British Guiana i ; Peru (Moyobamba) i . 



*Otus choliba decussatus'' (Licht.). Lichtenstein's Screech Owl. 



Sirix decussata Lichtenstein, Verz. Doubl. Berliner Mus., 1823, p. 59 (Bahia). 

 Pisorhina choliba decussata Hellmayr, Nov. Zool., XV, 1908, p. 90. 



Range: East-central and East Brazil (Bahia, Goyaz, etc.). 

 2: Brazil (Bahia). 



*Otus choliba margaritae'' Cory. Margaritan Screech Owl. 



Otus choliba margaritae Cory, Field Mus. Pub., No. 182, Om. Ser., Vol. I, 8, 1915, 

 p. 298 (Margarita I, off Venezuela. 



Range: Margarita I., (off Venezuela). 

 3 : Margarita Island. 



Otus ingens {SalvinY Salvin's Screech Owl. 



Scops ingens Salvin, Bull. Brit. Om. Club, VI, 1897, p. 37 (Ecuador). 

 Otus ingens Brabourne and Chubb, Bds. S. A., I, 1912, p. 75, No. 695. 



Range: Ecuador. 

 Otus atricapillus (Temm.). Black-headed Screech Owl. 



Strix atricapillus Temminck, PI. Col., II, 1823, pi. 145 (Brasil). 



Otus atricapillus Dabbene Bol. Soc. Physis I, 19 14, p. 306. 



Scops sanctae-catarinae Salvin, Bull. Brit. Om. Club, VI, 1897, p. 37.* 



Range: East and south Brazil, Paraguay, N. E. Argentine. 



• Otus choliba crucigerus Spix: Larger, and averaging more rufescent than 0. c. 

 decussatus (Licht.); wing (males), averaging about 1.70 mm. 



'' Otus choliba decussatus (Light.): Differs from 0. c. choliba (Vieill.) in average 

 smaller size and paler upper parts. 



'Otus choliba margaritae Cory: Similar to O. c. crucigerus (Spix) but smaller 

 and paler and the quadrate pale markings on the outer primaries much more white; 

 wing, 1.50 mm.; tail, 85 mm. 



Note. — The differences separating several of the supposed subspecies of Otus 

 choliba, while not very pronounced, are apparently constant and seem to represent 

 regional variation; unfortunately, sufficiently large series from the different regions 

 are not available to determine this question. 



•* Otus (choliba?) ingens Salvin: Similar to O. choliba (Vieill.), but more deeply 

 colored and larger; wing, 8.2 in. (This bird is unknown to me.) 



• Cf. HeUmayr, Nov. Zool., XVII, 1914, p. 414, in text. 



