GEXEKAL ADAI^TATIONS 345 



as a species; and (2) as inllucncing female choice of the must 

 ornamental males, and tlicrclure of use to each species in the 

 struggle for existence. The former I have, I tliink, proved to 

 be a true cause; the latter I reject for reasons given ii» my 

 Darwinism. I there give an alternative solution of the prol>- 

 lem which I still think to be fundnmontally correct and whicli 

 has been arrived at by Weismann and others from theoretical 

 considerations to whicli 1 may advert hiter on. 



C olouration of Insects 



Passing now to tlie order of insects wliich perhaps pxhil»its 

 the greatest range of colour-display in the wh(de of the organic 

 world — especially in the order Lepido])tera, we find the dif- 

 ficulties in the way of a purely utilitarian solution still greater. 

 Any one who is ac(iuainted with this order of insects in its 

 fullest development in the equatorial zone of the great conti- 

 nents, will recognise liow impossible it is to give any ade<piato 

 conception of its wealth of colour-decoration by a mere verbal 

 description, "^'et the attempt must be made in order to com- 

 plete the argument 1 am founding upon a consideration of the 

 whole of the facts of orc^anic colouration. 



Even in the temperate zones we have a rich display of colour 

 and marking in our exquisite little blues, our silver-spotted 

 fritillaries, our red-admiral, our peacock, and our orange-tip 

 butterflies, and on the Continent, the two swallow-tails, the 

 apollo butterflies, the fine Chaaxcs Jason, and many other*. 

 But these are absolutely as nothing compared to the wealth 

 of colour displayed in the eastern and western tropics, where 

 the average size is from two to three times ours, and the num- 

 bers, both in species and individuals at least ten times as great. 

 Not only is there every tint of red, yellow, Mue and gretMi, 

 on ground-colours of black or white an<l various slunles of 

 brown or buff, but we find the most vivid metallic hlues or 

 silky yellows covering a largi' j)orti<»ii of tlie wing-surface or 

 displayed in n variety of patteni< ihat i- almost bewildering 

 in its varietv and beauty. 



