FINN'S EXPERIMENTS ON BIRDS 269 



A. K. Marshall's memoir already often quoted, 1 and to 

 Frank Finn's interesting and important set of papers 

 especially devoted to this question. 2 After a long series 

 of experiments begun and conducted with a perfectly 

 open mind, upon Indian insect-eating vertebrates, Mr. 

 Finn supports the theories based upon Natural Selection 

 in the following words : 3 



' I conclude from these experiments 



' i. 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 butter- 

 flies, the " warningly-coloured " Danaina, Acraa viola, 

 Delias eucharis, and Papilio aristolochice ; of these the last 

 being the most distasteful, and the Danaina the least so. 



' 3. That the mimics of these are at any rate rela- 

 tively palateable, and that the mimicry is commonly 

 effectual under natural conditions. 



1 4. That each bird has to separately acquire its ex- 

 perience, and well remembers what it has learned. 



' That therefore on the whole, the theory of Wallace 

 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 sug- 

 gestion that animals may be forced by hunger to eat 

 unpalateable forms is also more than confirmed, as the 

 unpalateable forms were commonly eaten without the 

 stimulus of actual hunger generally, also, I may add, 

 without signs of dislike.' 



Mr. Finn concludes with some valuable suggestions as 

 to the conduct of future experiments. 



The chief objection that has been raised against the 

 theories of Bates and Fritz Muller, is the want of evi- 

 dence that birds are in any important degree the enemies 

 of butterflies. Many excellent observers have rarely 



1 Trans. Ent. Soc. Lond., 1902, p. 287. 



2 Journal, Asiatic Society of Bengal, Ixiv, pt. ii, 1895, p. 344 ; Ixv, pt. ii, 

 1896, p. 42 ; Ixvi, pt. ii, 1897, p. 528, and p. 613. 



s Ibid., Ixvi, pt. ii, 1897, pp. 667-8* 



