566 Mr. A. H. Thayer on 



The act of flight tends to obliterate pattern, by the 

 too quick substitution of one colour for another before the 

 eye. A black-and-white butterfly, therefore, tends to 

 look simply grej/ in flight. 



It is not necessary to conceive that a bird must find the 

 imitation flower on its proper plant, if the flower represent 

 a type common in the neighbourhood. A vast majority of 

 butterflies, including most members of Mimicry groups, 

 have the common dark Aving-tips of the fuscous colour 

 which causes this portion to seem lacking from the butter- 

 fly, leaving the lighter-coloured parts to represent a more 

 flower-like form. The white dots, so common on these 

 black tips, surprisingly aid the representation of space 

 helov.i the flower by supplying the average sharp details 

 that are to be seen down in the shady under-spaces, — 

 little glints of light on twigs, etc., — and their dark ground 

 IS rendered additionally transparent in appearance by 

 iridescence. 



If the foregoing arguments prove that the so-called 

 Warning-colours commonly cited do not exist mainly to 

 make their wearer conspicuous, it does not follow that 

 they may not still serve secondarily as Warning-colours. 

 When, for in.stance, they happen to fail to conceal, they 

 may then serve to warn. My main point is that they 

 first of all conceal. I suspect that the same principles 

 apply to striped wasps and hornets, and many other 

 insects called conspicuous. The yellow pattern unmistak- 

 ably allies their appearance to the pollen-covered flower- 

 interiors, making them far less conspicuous than an 

 unmixed need to be seen would have them. Yet when 

 seen, they may well profit by the pattern's recognizability. 



Can any one, once shown, as I here show, that butterflies' 

 patterns are not intrinsically the thing to make the wearer 

 conspicuous, and shown that i\\Qy arc wonderful representa- 

 tions of the flower-scenery I describe, believe that Natural 

 Selection has bungled, and wasted design of the most 

 intricate kind ? No, it is the beauty of the whole thing 

 that absolute fitness is the goal of all changes by Natural 

 Selection : — is, in fact, the only motive-power ; changing 

 all forms steadily towai'd itself. 



We see, then, that butterflies are imitation flowers, or 

 pictures of flower and background. This has escaped the 

 eye of zoologists. They see that fish wear representations 

 of under-water scenery; that forest animals are forest- 



