to be regarded as a performance slowly perfected through 
long generations through the selection of females, coy and 
hard to please. We must regard these “ Nuptial flights ”’ 
and wing-displays as the outward and visible signs of a state 
of ecstatic amorousness on the part of the males which, by 
their persistence and frequent recurrence, at last arouse 
sympathetic response in the females. They play the part 
of an aphrodisiac. Without them there would be no mating. 
In my Courtship of Animals those who will may pursue this 
subject further. 
Before closing this chapter mention must be made of 
the most remarkable wing-display to be found among birds, 
and of the equally remarkable uses to which they are put. 
The possessor of these wonderful appendages, for they are 
wonderful, is the argus pheasant of the Malay Peninsula 
and Borneo. Though efficient for short flights in jungles, 
all that is ever required of them, they would be quite useless 
in open country where an extended journey had to be made, 
or escape attempted from some vigorous enemy. And this 
because the secondary wing-quills—the quills attached to 
the forearm—are of enormous length, making, as we have 
remarked, sustained flight impossible. They have, indeed, 
come dangerously near losing their normal functions alto- 
gether. And this because they have passed over into the 
category of specialized ‘‘ secondary sexual characters.’ But 
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