AVES AR DEI DyG. 389 



Nyctiardca obscura Gray (nee Licht), Handl. B. III. p. 33, no. 10176 pt. 



(1871). 

 Nycticorax tayazu-guira, Sharpe, Cat. B. Brit. Mus. XXVI. p. 155 (1898); 



id. Hand-list B. I. p. 198 (1899); Martens, Vog. Hamb. Magalh. 



Sammelr. p. 21 (1900); Gates, Cat. Birds' Eggs Brit. Mus. II. p. 124 



(1902). 



GENERAL DESCRIPTION. 



Size. Adult male. (8823 Princeton University Collection, Province 

 of Buenos Aires, Argentina, July 1896). 



Total length, about 26.5 inches. 



Wing, 12.4. 



Culmen, 3.2. 



Tail, 5.3. 



Tarsus, 3.2. 



There does not appear to be a difference in size according to sex. 



Color. Adult male (cited). Breeding dress. General color grey with 

 a large dorsal area of deep greenish black. A like area on the head. 

 Below delicate grey, shading into pure white on the throat and abdomen. 



FIG. 205. 



Nycticorax tayasu-guira, adult male. 8823 Princeton University Collection. About \ nat- 

 ural size. 



Head : Forehead and continuous with it a line extending back above 

 the eye, white. Whole top of the head deep greenish black ; the 

 feathers lengthened and silky and reaching down on the nape for a short 

 distance. From the occiput a long (10 inches in bird cited) white cord- 

 like plume, which, when separated, is found to be composed of several 



