174 SEXUAL selection: BIEDS. PartIL 



colouring often characterises allied forms, that in three 

 species of Dacelo the male differs from the female only 

 in the tail being dull-blue banded with black, whilst 

 that of the female is brown with blackish bars ; so that 

 here the tail differs in colour in the two sexes in exactly 

 the same manner as the whole upper surface in the 

 sexes of Carcineutes. 



With parrots, which likewise build in holes, we find 

 analogous cases : in most of the species both sexes are 

 brilliantly coloured and undistinguishable, but in not a 

 few species the males are coloured rather more vividly 

 than the females, or even very differently from them. 

 Thus, besides other strongly-marked differences, the 

 whole under surface of the male King Lory {Aprosmictus 

 scapidatus) is scarlet, whilst the throat and chest of the 

 female is green tinged with red : in the Eujoliema sj^Ien- 

 dida there is a similar difference, the face and wins:- 

 coverts moreover of the female being of a paler blue 

 than in the male.^^ In the family of the tits (Parinse), 

 which build concealed nests, the female of our common 

 blue tomtit (Parus cseruhus) is " much less brightly 

 coloured" than the male; and in the magnificent Sultan 

 yellow tit of India the difference is greater.^^ 



Again in the great group of the woodpeckers,^* the 

 sexes are generally nearly alike, but in the Mega- 

 jncus validus all those parts of the head, neck, and 

 breast, which are crimson in the male are pale brown 

 in the female. As in several woodpeckers the head of 

 the male is bright crimson, whilst that of the female is 



22 Every gradation of difference between the sexes may be followed in 

 the parrots of Australia. See Gould's ' Handbook,' &c., vol. ii. p. 14-102. 



23 Macgillivray's ' British Birds,' vol. ii. p. 433. Jerdon, 'Birds of 

 India,' vol. ii. p. 282. 



2^ All the folloNving facts are taken from M. Malherbe's magnificent 

 ' Monographie des Picide'es,' 1861. 



