Chap. XVIII.] ORNAMENTAL COLORS. 27? 



second year the young male becomes -reddish-brown, in 

 the third year black, excepting the stomach, which, how- 

 ever, becomes quite black in the fourth or fifth year. There 

 is also a strongly-marked difference in color between the 

 sexes in Mycetes senicxdus and Cebus capucinus ; the young" 

 of the former and I believe of th*e latter species resembling 

 the females. With Pithecia leucocephala the young like- 

 wise resemble the females, which are brownish-black above 

 and light rusty-red beneath, the adult males being black. 

 The ruff of hair 'round the face of Ateles marginatus is 

 tinted yellow in the male and white in the female. Turn- 

 ing to the Old World, the males of Hylobates hoolock are 

 always black, with the exception of a white band over the 

 brows ; the females vary from whity-brown to a dark 

 tint mixed with black, but are never wholly black. 30 In 

 the beautiful Cercopithecus Plana the head of the adult 

 male is of an intense black, while that of the female is dark 

 gray ; in the former the fur between the thighs is of an 

 elegant fawn-color, in the latter it is paler. In the equally 

 beautiful and curious mustache monkey (Cercopithecus 

 cephus) the only difference between the sexes is that the 

 tail of the male is chestnut and that of the female gray ; 

 but Mr. Bartlett informs me that all the hues become 

 more stronglv pronounced in the male when adult, while 

 in the female they remain as they were during youth. 

 According to the colored figures given by Solomon Muller, 

 the male of Semnopithecus chrysomelas is nearly black, 

 the female being pale brown. In the Cercopithecus cyno- 

 sums and griseo-viridis one part of the body which is con- 

 fined to the male sex is of the most brilliant blue or green, 



30 On Mycetes, Rengger, ibid. s. 14; and Brehm, 'Illustrirtes Thier- 

 leben,' B i. s 96, 107. On Ateles, Desmarest, ' Mammalogie,' p. 75. 

 On Hylobates, Blyth, ' Land and Water,' 1867, p. 135. On the Seinno-. 

 pithecus, S. Muller, 'Zoog. Indischen Archipel.' tab. x. 



