Protective or Disguising Coloration, then, as we define it, falls into two 

 main divisions; the one including concealin g-colors mainly based on counter 

 shading, and the other including Mimicry, in almost all its branches. As 

 has already been explained, the goal of the former principle is the rendering 

 animals invisible in their normal haunts. Mimicry, on the other hand, aims 

 at deceptive visibility, it makes an animal look like something else than what it 

 really is. It will be seen that the latter principle is open to unlimited varia- 

 tions of method and result, whereas the former, as we have proved, is in its 

 main essentials strictly limited. There are innumerable kinds of solid objects 

 for animals to simulate in appearance, but there is only one way to make a 

 solid object in a natural lighting cease to appear to exist. Both these are 

 principles of disguising costume, and both are protective, yet they are funda- 

 mentally unlike. It becomes necessary to find a fully adequate name for the 

 stricter principle— a name less technical and more explicit than " counter 

 gradation." Obliterative Coloration is a phrase that will fit the general 

 principle, and Obliterative or Counter Shading may be used as a stricter term 

 for the essential root of it. 



We have, then, Obliterative Coloration, and Mimicry, as the two main prin- 

 ciples of Protective Coloration. Of the well-known and well-studied prin- 

 ciple of Mimicry, we shall give but few examples, and these chiefly from 

 among the lower orders. In the higher orders, it seems, as we have said, to 

 play a very insignificant part. 



Figs. 1-5 illustrate obliterative shading, pure and simple. Fig. 1 shows 

 an obliteratively shaded artificial model, contrasted with a monochrome one 

 which is colored precisely like the background, being covered with the very 

 same material; Fig. 2 shows a counter-shaded model inverted, and Fig. 3 

 the two models in the proper position, but with the direct top-light cut off 

 from the counter-shaded one. 



Fig. 6 shows a Barred Plymouth Rock hen, a bird which completely lacks 

 obliterative shading, photographed, out of doors, against a background made 

 wholly of the flat skins of similar hens. A more striking demonstration of 



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