214 Mr. 8. B. J. Skertchly on the 
female sailed down with stately flight, showing her white spots 
clearly, and commenced to woo. © Fora long time they circled 
over us about 6 inches apart, the female always uppermost 
and a little behind, so that she could see the emerald feathers 
of her mate. She did all the wooing. The flight was a 
sailing motion with a peculiar tremour of the wings, very 
unlike the quivering while feeding. The female during the 
whole time pointed her abdomen downwards. A solitary 0. 
flavicollis was about and made several feeble attacks on the 
lovers, which they totally- ignored. At length they settled 
high up in a tree and united, the female still uppermost. 
Darwin, dealing with the courtship of buttertlies, draws the 
conclusion that where the males are the brighter they are 
chosen by the females and where the females are the hand- 
somer the males are the selecting parties*. Hesays: “ Now 
the males of many butterflies are known to support the females 
during their marriage-flight ; but in the species just named 
[C. edusa, H. janira, Pieris, Thecla] it is the females which 
support the males ; so that the part which the two sexes play 
is reversed, as is their relative beauty. Throughout the animal 
kingdom the males commonly take the more active share in 
wooing, and their beauty seems to have been increased by the 
females having accepted the more attractive individuals ; but 
with these butterflies the females take the more active part in 
the final marriage ceremony, so that we may suppose that 
they likewise do so in the wooing; and in this case we can 
understand how it is that they have been rendered more 
beautiful.” 
The case of O. Brookeana is the exact opposite of this. 
The female is so much rarer than the male that Kiinstler, who 
has caught over a thousand males, has taken only fifteen 
females. Distant says ‘it is still exceedingly scarce”? f. 
The female is quite dull in comparison with her splendid 
mate, yet she does all the wooing, or did in the case described, 
which is probably a typical one. If sexual selection be really 
a fact of evolution, this is a case in which it can work. The 
females have unlimited chances of selection, and the males may 
be supposed to be only too glad to accept any lover. Indeed, 
I can only imagine sexual selection acting where there is a 
disparity of numbers between the sexes. Selection implies 
rejection, and where the sexes are practically equal in number, 
though the handsomer individuals may choose or be chosen 
* “Descent of Man,’ ed. 2, p. 319. 
+ Rhop. Mal. p. 331. 
