Chap. XVIII. ORNAMENTAL COLOURS. 291 



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. Turning to the Old AVorld, the 

 males of Hylohates lioolock 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 

 Cercopitliecus diana the head of the adult male is of an 

 intense black, whilst that of the female is dark grey ; in 

 the former the fur between the thighs is of an elegant 

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

 beautiful and curious moustache monkey (Cercoj)ithecus 

 ceplius) the only difference between the sexes is that 

 the tail of the male is chesnut and that of the female 

 grey ; but Mr. Bartlett informs me that all the hues 

 become more strongly pronounced in the male when 

 adult, whilst in the female they remain as they were 

 during youth. According to the coloured figures given 

 by Solomon Miiller, the male of Semnojpithecus cJiry- 

 somelas is nearly black, the female being pale brown. 

 In tlie Cercopithecus cynosurus and griseo-mridis 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. 



Lastly, in the Baboon family, the adult male of Cyno- 

 cephalus hamadryas differs from the ^female not only by 

 his immense mane, but slightly in the colour of the hair 

 and of the naked callosities. In the drill (Cynocej^halus 



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

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

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

 pithecns, S. Miiller, 'Zoog. Indischeu Arckipel.' tab. x. 



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