FAMILY ACCIPITRIDAE 255 



ISCHNOSCELES CAERULESCENS NIGER Du Bus 



Ischnosceles niger Du Bus, Bull. Acad. Roy. Sci. Lett. Beaux Arts Belgique, 

 vol. 14, pt. 2 (for August) 1847, p. 102. (Mexico.) 



Adult, blackish slate ; tail bands white, occasionally with the upper 

 one faintly tinged with buff; slightly larger. Wing, male 290-305, 

 female 310-332 mm. 



Iris "bright red ; the cere, eyelids, and mouth corners dull gray ; 

 the bill black with bluish cast; the tarsi and toes orange or red- 

 orange; the claws black" (Sutton, Wilson Bull., 1954, p. 237). 



Measurements. — Males (5 from Mexico, Guatemala, and western 

 Panama), wing 290-305 (299.8), tail 215-240 (230.2), culmen from 

 cere 18.6-19.9 (19.3), tarsus 81.0-90.0 (84.2) mm. 



Females (4 from Mexico and western Panama), wing 310-332 

 (316.3), tail 233-247 (237.6), culmen from cere 20.0-21.5 (20.5), 

 tarsus 88.0-93.4 (90.1) mm. 



This subspecies is found from north-central Mexico through the 

 tropical lowlands of Central America to central Panama. 



Resident. Tolerably common; found locally, in western Panama, 

 east to the Canal Zone. 



Records for this race follow : 



Chiriqui : Divala, Nov. 24, 1900 (Bangs, Auk, 1901, p. 358). 

 Veraguas : Mina de Chorcha (Salvin, Proc. Zool. Sec. London, 1870, p. 216). 

 Herrera : El Rincon ; Santa Maria. 



Canal Zone: Atlantic slope, near the railroad (Lawrence, Ann. Lye. Nat. 

 Hist. New York, vol. 7, 1861, p. 289) ; Barro Colorado Island. 



Birds from the Canal Zone and Herrera show intergradation to- 

 ward the next race. 



ISCHNOSCELES CAERULESCENS BALZARENSIS (W. L. Sclater) 



Geranospisa caerulescens balsarensis W. L. Sclater, Bull. Brit. Orn. Club, vol. 

 38, March 4, 1918, p. 45. (Balzar, Provincia de Guayas, Ecuador.) 



Adult like Ischnosceles caerulescens niger but grayer; pale bars 

 on tail tinged with buff ; size somewhat smaller. 



Measurements. — Male (1 from northwestern Colombia), wing 

 279, tail 217, culmen from cere 18.2, tarsus 73.0 mm. 



Females (8 from Panama and Colombia), wing 288-298 (290), 

 tail 218-237 (229), culmen from cere 19.2-20.4 (20.1), tarsus 81.7- 

 87.0 (83.3) mm. 



Resident. Found locally from the eastern sector of the Province 

 of Panama eastward. 



