BORNEAN ARGUS PHEASANT 155 



full-grown bird, the central pair is seldom more than half the length which it will 

 ultimately attain. 



Third Year Male. — I have examined birds which had completed this moult, and 

 the change was only another step towards the perfection of the adult. It is probable 

 that the bird can breed at this age, as I have found evidences that its display is regular, 

 and birds in this state of development were twice trapped in possession of dancing 

 arenas. But it is also as certain that, judging by the rate of growth observed, one or 

 two magnificent males in my possession must be fully five years of age, and I believ6 

 that this is the moult at which they attain their most perfect plumage. 



Ocelli. — Charles Darwin in his " Descent of Man " has given an elaborate descrip- 

 tion of these ornaments on the secondary feathers of the Argus Pheasant. His 

 description is very precise and exact, but his derivation of the perfect ocelli from 

 "elliptic ornaments" is only one of many such origins which might be adduced. This 

 elaboration may be studied in any one moult by examining the series of secondaries 

 from the first to grow out to the last which completes the moult ; or we may compare 

 the feathers of successive moults from the first year onward ; or, again, we may take 

 any one feather and follow the gradual diminution and disappearance of the ocelli, both 

 at the proximal and distal ends of the line of ornaments. This will reveal the fact that 

 not one but several methods of development may be deduced, each of which of course 

 depends on the amount and distribution of pigment. 



As to the idea that conscious visual sexual selection has brought about this 

 wonderful plumage I have already given my opinion. It seems impossible to conceive, 

 much as w^e should like to believe in it, and personally, I should be willing to strain 

 a point here and there to admit this pleasant psychologically aesthetic possibility ; but 

 I cannot. I remember once in the heart of British Guiana one of my servants entered 

 the bungalow with a dish of venison for the evening meal, and on the sleeve of his coat 

 was a hemipterous insect, a true bug, with gorgeous gauzy wings of rose and gold. 

 For five minutes I studied them with a hand-lens, and on the folded fan of tissue 

 pinions I found the ocelli of the Argus, as perfect, as truly deceiving in the sense of 

 appearing to revolve within sockets ; with the same light-shaded reflection in each, with 

 pigment even more brilliant and pattern more complex. If I grant that esthetic 

 appreciation and selection based upon that phenomenon is the only explanation of the 

 eyes of the Argus, then I must acknowledge that the same holds true for the female 

 hemipterous bug with her faulty, faceted means of vision. If, however, it is the 

 general colour and movement and insistence of display in each case, which acts sub- 

 consciously through the combined sense impressions, I feel that I am within the 

 bounds of probability in each organism. As to the question of the extreme refinement, 

 the needlessly microscopic exactness, the amplitude of detail of the ornamentation, I 

 candidly answer I do not know. If it be not a mere impetus of perfection, the accumu- 

 lated result of the generalized sexual selection on the part of the hen (which assuredly 

 exists), carried beyond necessity, then, qiiien sabe ! The answer may come soon. 

 When it does it will probably be a complex of factors. We are at least learning not 

 to explain all colouring by protection, or warning or sexual theories, but by a realization 



