}5? The Descent of Man. Part II 



the males alone of Sitana possess a throat-pouch ; and this is 

 splendidly tinted with blue, black, and red. In the Frvdotretns 

 tfiiuis of Chile the male alone is marked with spots of blue, 

 green, and coppery-red." In many cases the males retain the 

 same colours throughout the year, but in others they become 

 much brighter during the breeding-season ; I may give as an 

 additional instance the Calntes maria, which at this season has a 

 bright red head, the rest of the body being green.™ 



Both sexes of many species are beautifully coloured exactly 

 alike ; and there is no reason to suppose that such colours are 

 protective. No doubt with the bright green kinds which live 

 in the midst of vegetation, this colour serves to conceal them , 

 and in N. Patagonia I saw a lizard (Practotretus multimaculatus) 

 which, when frightened, flattened its body, closed its eyes, and 

 then from its mottled tints was hardly distinguishable from the 

 surrounding sand. But the bright colours with which so many 

 lizards are ornamented, as well as their various curious appen- 

 (^ages, were probably acquired by the males as an attraction, 

 and then transmitted either to their male offspring' alone, or to 

 both sexes. Sexual selection, indeed, seems to have played 

 almost as important a part with reptiles as with birds ; and the 

 less conspicuous colours of the females in comparison with the 

 males cannot be accounted for, as Mr. Wallace believes to be the 

 case with birds, by the greater exposure of the females to danger 

 during incubation. 



CHAPTER XIII. 

 Sbcondaet Sexual Characters of Bires. 



.Sexual differences — Law of batMe — Special weapons — Vocal organs — 

 Instrumental music — Love-antics and dances — Decorations, permanent 

 .ind seasonal — Double and single annual moults — Display of ornaments 

 by the males. 



Seoondabt sexual characters are more diversified and con- 

 spicuous in birds, though not perhaps entailing more important 

 changes of structure, than in any other class of animals. I shall, 

 therefore, treat the subject at considerable length. Male birds 

 sometimes, though rarely, possess special weapons for fighting 



" For Proctotretus see ' Zoology the Indian Calotes, see ' Reptiles of 



,f the Voyage of the "Beagle:" British India,' by Dr. Gunther, p. 



Reptiles,' by Mr. Bell, p. 8. For 14.3. 



the Lizards of S. Ati-ira, see ' Zoology " Gunther in ' Proc. Zoolog. Soc' 



■>( S. Africa; Kejitiies,' liy Sir 1870, p. 778, with a coloured 



.Vndrew Smith, pL '.'> and :i9. For Heure. 



