V ° 1 190^ 111 ] Clark, Black Forms of the Genus Ccereba. 393 



forms are common, and sometimes occur only in restricted portions 

 of the habitat of the species, as in the case of the black phase of 

 one of these Honey Creepers (C. wellsi). A rather interesting 

 and somewhat similar phenomenon is shown in the females of the 

 American swallow-tailed butterfly (Papilio glaucus Linn.) which 

 are yellow like the males in the northern part of the range of the 

 species, but sooty black in the south. 



In the case of these Honey Creepers, the black colored birds, 

 possessing a well marked dominance over those of normal color, 

 have gradually increased in proportion, until the typical phase has 

 been practically eliminated from those islands on which the black 

 phase occurs. 



As the evidence seems to show that these two black Honey 

 Creepers are conspecific with the normal forms inhabiting the 

 same islands, the species on St. Vincent must be known as Ccereba 

 atrata (Lawr.), 1 that name having page precedence over C. sac- 

 charina (Lawr.), 2 applied to the bird in the normal phase of plum- 

 age. The Grenada species must stand as Ccereba weUsi (Cory). 3 



The two birds with their synonymy and distribution are as 

 follows: — 



Ccereba atrata (Lawr.). St. Vincent. 



Normal form. 

 Molasses Bird; Sucrier; Yellow Breast. 



Certhiola saccharina Lawr., Ann. N. Y. Acad. Sci., Vol. I, p. 151 (1878); 

 Lawr., Proc. U. S. Nat. Mus., Vol. I, pp. 190, 487 (1878); Cory, List 

 Birds W. I., p. 9 (1885); Ridgw., Proc. U. S. Nat. Mus., Vol. VIII, 

 pp. 28, 30 (1885); Cory, Auk, Vol. Ill, p. 50 (1886); Birds W. I., 

 p. 64 (1889); Scl., Cat. Birds Brit. Mus., Vol. XI, p. 42 (1886); [Clark], 

 W. I. Bull., Vol. V, p. 86 [1904]. 



Ccereba saccharina Cory, Auk, Vol. VIII, p. 39 (1891); Cat. W. I. Birds, 

 pp. 17, 116, 134 (1892); Ridgw., Birds No. & Mid. Am., Vol. II, p. 

 415 (1902); Mayn., Cat. Birds W. I., p. 26, No. 249 (1903). 



i Lawrence, Ann. N. Y. Acad. Sci., Vol. I, 1878, p. 150. 



2 Lawrence, Ann. N. Y. Acad. Sci., Vol. I, 1878, p. 151. 



3 Cory, Auk, Vol. VI, 1889, p. 219. 



