CERCOMACRA. 45 



two-thirds the length o£ the'tarsus. The wing is rounded, the fifth, 

 sixth, and seventh primaries longest and equal and the fourth 

 about equal to the eighth. The tail is long and much graduated, 

 the outer feather on each side beino- about half the leno-th of the 

 middle ones. Coloration: male and female difi'erent. 



Key to the Species. 



A. Bend of wing and margins of upper 



wing-coverts uniform with the [p. 45. 



rest of the upper surface C. cinerascens hnmaciilata, S , 



a. Under surface ochreous brown .. . C. cinerascens immaculata, 5 , 



B, Bend of wing and margins of upper [p. 46. 



wing-coverts white in contrast 



to the rest of the upper sur- [p. 46. 



face C. fjjrannina saturatior, S, 



h. Under sui'face bright chestnut- [p. 46. 



rufous C. tyrann ina saturatior, $ , 



377. Cercomacra cinerascens immaculata. 

 Thb British Guiana Ant-"Wren. 



Gercomacra cinerascens (nee Scl.) Salvin, Ibis, 18S5, p. 426 (Bartica 

 Grove, Camacusa) ; Sclater, Cat. B. Brit. Mus. xv. p. 264, 1890, part, 

 specimens a-cl ; Brabom-ne & Chubb, B. S. Amer. i. p. 204, no. 2050 

 part, 1912. 



Cercomacra cinerascens immaculata Chubb, Bull. Brit. Orn. Club, 

 xxxviii. p. 84, July 25, 1918. 



Adult male. General colour above and below blackish slate- 

 colour ; primary and secondary quills blackish, with pale grey 

 edgings to the inner webs ; tail somewhat darker than the back, 

 with indistinct wavy bars and narrow white tips to the feathers ; 

 under surface slightly paler than the back. 



Total length 147 ram., culmen 17, wing 65, tail 57, tarsus 20. 



The type, which is in the Mc( -onnell collection, was collected 

 on the Supenaam River in March 1910. 



This subspecies differs from C cinerascens cinerascens in being 

 darker (both male and female), above and below, in the absence of 

 the white dorsal patch, and the uniform upper wing-coverts. 



According to llellmayr (Nov. Zool. xii. p. 287) ('. napensis Scl. 

 is synonymic with C. cinerascens Scl. The Guiana bird therefore 

 is easily s(![)arablo from the typo of the latter by the characters 

 given above. 



