482 University of California Piiblications in Zoology [Vol. 11 



already quoted (p. 430) also supports the latter statement. The 

 ten pages of evidence given by Poulton (1908) also supports the 

 view that birds, even though they do not feed to any considerable 

 extent on these insects, do, occasionally at least, feed upon them. 

 Mason and Lefroy (1912), after a study of the food of the birds 

 of India, state: "Butterflies do not form any appreciable pro- 

 portion of the food of any one species of bird, though a good 

 many birds take these insects at times. ' ' 



Although identification of the butterflies found in the stom- 

 aelis has often been impossible, yet it is certain that they often 

 belonged to separate families. The difference between the pierid 

 butterfly, Eurymus eurytheme, and the nymphalid butterfly, 

 Eugonia californica, is great enough to show that there is little 

 choice shown. This evidence is supported by the work of Manders 

 (1911). He concludes: "There is no bird in Ceylon known to 

 eat butterflies that distinctly discriminates as an adult between 

 one species of butterfly and another." Manders also goes so far 

 as to say : ' ' The fact that there is no discrimination shown by 

 adults leads one to conclude either that few or no tasting experi- 

 ments were undertaken in youth, or, what is more probable, that 

 their taste with regard to them is indifferent." One important 

 criticism that can be made of Mander's work is that he depended 

 entirely on observation. The criticism bears less weight, how- 

 ever, since the insects under observation were of sufficient size 

 and conspicuousness to make the observational method more 

 dependable. 



Any one who has watched a bird catch a butterfly must 

 necessarily be impressed with the skill needed. Certain agility 

 on the part of the butterfly must aid greatly in protecting it 

 from attack. Further study may demand a change of emphasis 

 from protective coloration to the protection afforded by the but- 

 terfly's ability to elude its pursuer. 



There appears to be evidence that birds seldom attack butter- 

 flies, thus lending support to the theory that they are protected. 

 On the other hand, it can be seen that there is evidence that 

 butterflies are taken regularly as food by some birds. There 

 are doubtless many factors which enter into the problem which 

 have not as vet been considered. Hence until further evidence 



