THE YOUNG LIKE THE ADULT FEMALES. 193 
C«. 
Aj>. 
XVI. 
the female of the latter species having the 
er surface pure white, whilst the female P. apoda is 
^ e I' °rown beneath. So, again, as I hear from Professor 
'-"ton, the males of two species of Oxynotus (shrikes), 
. c u represent each other in the islands of Mauritius 
k' B°urbon, 8 differ hut little in colour, whilst the 
^ales differ much. In the Bourbon species the female 
( . 1'ears to have partially retained an immature condition 
. Plumage, for at first sight she “might he taken for 
^ e young of the Mauritian species.” These differences 
0 j. a ! be compared with those which occur, independently 
c ejection by man, and which we cannot explain, in 
a rf ain s uh-hreeds of the game-fowl, in which the females 
t; Ver y different, whilst the males can hardlv be dis- 
Vished. 9 
( li(f S ^ account so largely by sexual selection for the 
tl) eie . aces between the males of allied species, how r can 
• differences between the females be accounted for 
n all 
% 
*<I a 
ordinary cases? We need not here consider the 
e,e s which belong to distinct genera ; for with these, 
W 
jj'Ptation to different habits of life, and other agencies, 
have come into play. In regard to the differences 
"’ill 
^en the females within the same genus, it appears to 
(ho a ^' 10s l' cert ain, after looking through various large 
ill 1 1 >s> that the chief agent has been the transference, 
fiif.j 1 ® rea ter or less degree, to the female of the cha- 
1^ ] trs acquired by the males through sexual selection. 
y ( . r 19 several British finches, the tw r o sexes differ either 
■ lightly or considerably ; ami if w r e compare the 
V.h' eS ^ ie greeufinch, challinch, goldfinch, hull- 
> crossbill, sparrow, &e., we shall see that they 
* ‘ Tlie Malay Archipelago,’ vol. ii. 1869, p. 394. 
‘ e ? e secies are described, with coloured figures, by M. F. Pollen, 
* 1864, p. 275 
v ar kt.on of ynimals, Ac., under Domestication,’ vol. i. p. 251. 
V °^. II. 0 
