206 
SEXUAL SELECTION: BIRDS. 
PAR* 1 
those with duller plumage and grey legs were the i |lil e [ 
or the young. In tin Australian tree-creeper 
ieris erythrops) the female differs from the null* 1 1 
‘•being adorned with beautiful, radiated, rufous u^ 1 ' 
“ ings on the throat, the male having this part d' 11 ^ 
“plain.” Lastly in an Australian night-jar “the h' 111 ' 1 ^ 
“always exceeds the male in size and in the brill' tl ° g 
“of her tints; the males, on the other hand, have ^ 
“ white spots on the primaries more conspicuous u )tl 
“ in the female.” 25 
We thus see that the cases in which female bii'^ s ! ! , 
more conspicuously coloured than the males, with 
young in their immature plumage resembling the ad 1 
males instead of the adult females, as in the p reV1 °- n 
class, are not numerous, though they are distribute^ 
various Orders. The amount of difference, also, 
the sexes is incomparably less than that which freq l,t f 
occurs in the last class ; so that the cause of the h' f e 
ence, whatever it may have been, has acted on tb 0 
males in the present class either less energetically ° T ^ {l 
persistently than on the males in the last class. ' ^ 
Wallace believes that the males have had their cd 0 
I nr the Milvngo, see ‘ Zoology of the Voyage of tho 
Birds, I All , p. lt>. For the Clinracteris and night-jar (Eur 0 ®t°P j jl c 
see Gould s ‘ Hanilbook of the Binla of Australia, ’ vol. i. p. 602 1,1 
Tho Now Zealand shield rake ( Tadorna variegatd ) offers a quit 0 
lous ease . the head ot the female is pure white, and her book 1 jgid 
th"n that of tho male; the head of the male is of a rich dark l)1 . ,,d 
colour, and his hack is clothed with finely pencilled d nt|L ' <1 ' ^jfd 
feathers, so that ho may altogether be considered ns tho more 1 ^ 
of the two. Ilo is larger and more pugnacious than the d' lUt ' Ajc ; 
does not sit on the eggs. So that in nil these respects this *1^. 
comes under our first class of oases ; but Mr. Sclater 0 P r0 °'c tiA 
Soc.’ I860), p. led) was much surprised to observe that the young 
screes, when about three months old, resembled in their dark b^pul ' 1 
necks the adult males, instead of the adult females; so that d { t ]i 0 
appear in this case that tho feinalos have been modified, wl11 ’ 
males and tho young have retained a f, inner state of plumage- 
