604; PROF. E. B. POITLTON : Kl TUBAL SELECTION 



" I conclude from these experiments : — 



" 1. That there is a general appetite for butterflies among 

 insectivorous birds, even though they are rarely seen when wild 

 to attack them. 



" 2. That many, probably most species, dislike, if not intensely, 

 at any rate in comparison with other butterflies, the ' warningly- 

 coloured ' DanaincB, Acrcsa viola, Delias eucharis, and Papilio 

 aristolocliicB, of these the last being the most distasteful, and the 

 Banaincd the least so. 



" 3. That the mimics of these are at any rate relatively|palatablei 

 and that the mimicry is commonly effectual under natural con- 

 ditions. 



" 4. That each bird has to separately acquire its experience, 

 and well remembers what it has learned, 



"That therefore on the whole, the tlieory of AVallace and 

 Bates is supported by the facts detailed in this and my former 

 papers, so far as they deal with Birds (and with the one Mammal 

 used). Professor Poulton's suggestion that animals may be 

 forced by hunger to eat unpalatable forms is also more than 

 confirmed, as the unpalatable forms were commonly eaten with- 

 out the stimulus of actual hunger— generally, also, I may add, 

 without signs of dislike." 



Mr. Finn concludes with some very valuable suggestions as to 

 the conduct of future experiments. 



The chief objection that has been raised against the theories 

 of Bates and Fritii Miiller, and which was often insisted on in 

 the discussion at the Entomological Society, is the want of 

 evidence that birds are in any important degree the enemies of 

 butterflies. Many excellent observers have rarely seen butter- 

 flies attacked by birds. On the other hand, the Miilleriau 

 theory only presupposes that the young birds test the palatability 

 of a few members of each convergent group in their locality and 

 henceforward avoid all the members, so that the recent tendency 

 to explain so many uf these resemblances on Miilierian rather 

 than on Batesian lines is in harmony with the conclusion that 

 the members of such groups are not greatly attacked. 



As regards butterflies which do not exhibit these resem- 

 blances, I may point out that it is impossible to exhaust the 

 details of the struggle for existence even as regaids a single 

 species, in the intervals of the time devoted to collecting. Such 

 an investigation would demand the whole time of a first-rate 



