Chap. XVIII. 
OBNAMENTAL COLOUBS. 
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 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.^® In the beautiful 
Cercopithecus diana the head of the adult male is of an 
intense black, Avhilst that of the female is dark grey ; in 
the former the fur between the thighs is of an elegant 
fawn-colour, in the latter it is paler. In the equally 
beautiful and curious moustache monkey {Cercopithecus 
eephus) 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 Muller, the male of Semnopithecus chry~ 
somelas is nearly black, the female being pale brown. 
In the Gercopithecus cynosurus and griseo-viridis 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 {Cynoceplialus 
On Mycetes, Bengger, 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 Semno- 
pithecus, S. Muller, ‘ Zoog. Indischen Archipel.’ tab. x. 
u 2 
