310 PROCEEDINGS OF THE ACADEMY OF [June, 



startling difficulty, yet it is evident from the behavior of the lizards 

 that they fully expected the larva to be palatable, in itself a strong 

 confirmation of the suggestion that nearly all such larvae are palat- 

 able" (p. 243). This is another argument that cannot be accepted 

 unless it is also applied to the rejections of conspicuous larvae upon 

 trial, and this latter evidence rather than disregard is all the experi- 

 ments yield that is worth any consideration. In fact, if impartially 

 applied, this argument would do away with the experimental evidence 

 of the efficacy of warning colors in all cases in which the insects were 

 tasted before refusal. In other words, it would be just as fair to 

 presume that these conspicuous larvae also were expected to be 

 palatable, "in itself a strong confirmation of the suggestion that 

 nearly all such larvae are palatable." 



The experiments performed by R. I. Pocock, Superintendent of 

 the London Zoological Gardens, like those just reviewed, cover a 

 variety of vertebrate orders. A far larger number of species both 

 of predators and prey were used than in any other experiments yet 

 recorded. The captive animals included twenty-six species of 

 mammals, ninety-six of birds, and seven of lizards, of which only 

 six birds and one lizard occur naturally in England. The insects 

 used were, of course, chiefly native. Even if we believe that experi- 

 mental results have any value as indicating natural behavior, we 

 can only conclude that the conditions of these experiments invalidate 

 the findings, for of what possible value can it be to know the likes 

 and dislikes of exotic animals for British insects? 



The account of these experiments is in P. Z. S. Lond., 1911, pp. 

 809-864. Mr. Pocock thinks his experimental results have "an 

 important bearing upon the criticism sometimes advanced against 

 the theory of warning coloration and mimicry as applied to butter- 

 flies, namely, that birds under natural conditions are seldom seen to 

 eat these insects. Hence it has been inferred that birds cannot be 

 reckoned as serious enemies of butterflies. Whatever may be the 

 explanation of the circumstance," Pocock says, "I am tolerably 

 sure, from the behavior of the two classes of animals when pitted 

 against one another that the inference drawn therefrom is erroneous. 

 The insectivorous birds in our aviaries seemed to know at once what 

 the butterflies were; they were on the alert the moment one was 

 liberated and pursued it with determination and precision, following 

 its every turn and twist, and either catching it upon the wing or 

 pouncing upon it after settling. It is true that this predatory 

 deftness may have been acquired in relation to the chase of insects 



