694 THE DESCENT OF MAN 



caraya are grayish yellow and like each other; in the 

 second year the young male becomes reddish brown; in 

 the third, black, excepting the stomach, which, however, 

 becomes quite black in the fourth or fifth year. There is 

 also a strongly marked difference in color between the 

 sexes of Mycetes seniculus and Cebus capucinus ; the young 

 of the former, and I believe of the latter species, resem- 

 bling the females. Witb Piihecia leucocephala the young 

 likewise 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 Hylolates 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." In 

 the beautiful Oercopithecus diana, 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 beautiful and curious mustache monkey {Oercopithecus 

 Cephas) 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 

 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 Oercopithecus cynosurus and griseovi- 

 ridis one part of the body, which is confined to the male 

 sex, is of the most brilliant blue or green, and contrasts 

 strikingly with the naked skin on the hinder part of the 

 body, which is vivid red. 



*• On Mycetes, Reugger, ibid., s. 14; and Brehm, "Illustrirtes Thierleben," 

 B. i. s. 96, 107. On Ateles, Desmarest, "Mammalogie, " p. 75. On Hylobales, 

 Blyth, "Land and Water," 1867, p. 135. On the SemnopitheouB, 8. MQller, 

 "Zoog. Indischen ArchipeL," tab. x. 



