92 
SEXUAL SELECTION: BIRDS, 
Part II. 
It may well be asked, could such artistically-shaded 
ornaments have been formed by means of sexual selec- 
tion? But it will be convenient to defer giving an 
answer to this question until w^e treat in the next 
chapter of the principle of gradation. 
The primary wing-feathers, which in most gallina- 
ceous birds are uniformly coloured, are in the Argus 
pheasant not less wonderful objects than the secondary 
wing-feathers. They are of a soft brown tint with 
numerous dark spots, each of which consists of two or 
three black dots witli a surrounding dark zone. But 
the chief ornament is a space parallel to the dark-blue 
shaft, which in outline forms a perfect second feather 
lying within the true feather. This inner part is 
coloured of a lighter chesnut, and is thickly dotted 
with minute white points. I have shewn this feather to 
several persons, and many have admired it even more 
than the ball-and-socket feathers, and have declared 
that it was more like a work of art than of nature. 
Now these feathers are quite hidden on all ordinary 
occasions, but are fully displayed when the long secon- 
dary feathers are erected, though in a wddely different 
manner ; for they are expanded in front like two little 
fans or shields, one on each side of the breast near the 
ground. 
The case of the male Argus pheasant is eminently 
interesting, because it affords good evidence that the 
most refined beauty may serve as a charm for the 
female, and for no other jiurpose. We must conclude 
that this is the case, as the primary wing-feathers are 
never displayed, and the ball-and-socket ornaments are 
not exhibited in full perfection, except when the male 
assumes the attitude of courtship. The Argus pheasant 
does not possess brilliant colours, so that his success in 
courtship appears to have depended on the great size of 
