460 Thayer, Concealing Coloration. |_Oct. 



CONCEALING-COLORATION: A DEMAND FOR INVES- 

 TIGATION OF MY TESTS OF THE EFFACIVE 

 POWER OF PATTERNS. 



BY ABBOTT H. THAYER. 



In 1896 naturalists received from me ('The Auk,' April, 1896) 

 the first analysis of the effacing-power of counter-shading, and 

 in the same article the discovery of the concealing-power of pat- 

 terns (then accredited by me, through misinformation, to H. W. 

 Bates as a previous discoverer). Soon after, I secured acceptance 

 for the counter-shading part by proving that it was possible so to 

 counter-shade an object as to make it invisible. The same inevit- 

 able recognition awaits the similar effacing-power of pattern, whenever 

 naturalists will come and study my proofs. I, to whom they already 

 acknowledge their debt for the discovery of counter-shading, 

 demand to be trusted that it is I alone who am in a position to 

 judge whether they need to study these proofs. 



It begins to seem necessary to try once more to convince those 

 naturalists who oppose me that they are acting on a misunder- 

 standing, reiterating statements that I have never contradicted, 

 and refusing either to notice what I do state, or to study optics 

 itself, which is purely and simply the thing I am communicating 

 to them. 



Up to the present moment there is not a naturalist in the world 

 who has seen any representative number of my tests of animals' 

 costumes' background-reproduction, or who has any adequate 

 conception what they really are. A few naturalists have seen a 

 very few of them; and in the main those who have seen the most 

 are the most convinced, while those who have seen none are the 

 ones who are most loudly ridiculing the whole thing. It is among 

 these latter that there exists an idea that the remarkable disap- 

 pearance of each brilliant costume against a certain background 

 merely proves my ingenuity. 



When, for instance, I take a bird and spend an hour in finding 

 a type of vegetation, situation and view-point in which he is 

 absolutely indistinguishable, this operation is open to two inter- 



