INSECTS 249 



coupling of Omithoptera brookiana} In all the species of 

 this genus the females are larger than the males, and sombre 

 in colouring, while the males are very brilliant. In this 

 particular species the male is mostly black, with green marks 

 on the wings, and a broad collar of crimson. The male seen 

 by Skertchly was sipping the flowers of a tree, vibrating its 

 wings rapidly like a hawk-moth, the vivid green markings 

 flashing out in the sunlight. The female came and " did all 

 the wooing." They circled about in flight with the female 

 above and a little behind, so that she could see the emerald 

 marks of the male. There is no evidence of competition 

 here, although the males are so numerous that one collector 

 caught over a thousand of them, and only fifteen females. 

 The observer remarks : " One would expect the amorous 

 swains to swarm around coy maidens instead of behaving 

 like lepidopterous Josephs." He also writes : " It certainly 

 seemed to me that, being mature, she accepted the first male 

 she met." These observations were made in Borneo. 



Moseley, 2 however, in the Aru Islands, saw a dozen males 

 of Ornithoptera poseidon fluttering round and mobbing a 

 single female. But it is difficult to believe that a female in 

 such circumstances had the power of choosing the most 

 beautiful male : in the confusion and crowding she could 

 not possibly see which was the brightest. The luckiest and 

 most active male would probably be successful. 



The above remarks apply to cases in which the males are 

 more brilliant than the females, and those in which the sexes 

 are similar. There are, however, cases among Lepidoptera, 

 as in birds, in which the female is more brilliant and 

 beautiful than the male. The differences in these cases are 

 not extreme, not nearly so great, for example, as in dimorphic 

 species exhibiting mimicry. In the British species of butter- 



1 Ann. Mag. Nat. Hist. (6) iv. 1889, p. 213. \ 

 2 Naturalist on the Challenger, p. 373. 



