the Coloration of Eggs. 543 



eggs, T did not happen to hit on the inipleasantest grades. 

 Or it may not. In either case the principle of graded 

 preference — of progressive elimination — remains, and this 

 is all that is necessary for our purpose. Actually I should 

 say that their lowest-placed eggs were to the mongoose and 

 rat about what Mylothris and Belenois are to insectivorous 

 birds. Both genera are, at any rate, so well protected as to 

 possess many mimics. 



In favour of Preference. 



The remarks of two, I think, of the speakers at the 

 meeting suggested strongly that preferences are, perhaps, 

 sometimes seen in the field — the special search, for example, 

 of certain of the British Corvidae for particular eggs ; and 

 an interesting question, and one that might perhaps be 

 fairly easily answered, is : Do any of the Corvidje, as a 

 regular practice, search thus for relatively well-concealed 

 eggs, as those of plovers and game-birds, while conspicuous 

 nests in the same neighbourhood, remain for the time being 

 untouched ? If this were found to happen, the observation 

 would, at any rate, be suggestive, even if the contents of 

 some of the conspicuous nests were also eventually to fall a 

 prey. 



I have already referred to the different flavour and con- 

 sistency of each of the few eggs that we ourselves most 

 commonly use for food. Mrs. A. L. Sclater, who was 

 staying with us at the time of my rat-experiments in 1913, 

 told me then that, as a girl, she, with her brothers, 

 used sometimes to eat birds' eggs, and that they learned 

 to avoid one common e^^, she had forgotten whether 

 Thrush or Blackbird, owing to its unpleasant taste. It 

 was, therefore, with the greatest interest that I read the 

 following passage in one of two letters, full of information, 

 which Mr. H. M. Wallis was so kind as to write me on 

 April 15th and 26th, respectively, after being present at 

 the discussion on the subject : " Kelative palatability 

 of eggs. I have in all cases of difficulty sucked eggs of 

 any value rather than trust to the blow-pipe, and have found 



