the Culoruliun of /-^.y*'. 533 



Present Experiments. 



Ill Prof. Newton's words, the subject was " worthy of 

 much more attention than it has received." In July of 

 1911, while thinking out the general bearing of my results 

 from insectivorous birds, I saw that they suggested the 

 explanation for distinctiveness and diversity — in, at any rate, 

 insects — that I have described in the first part of this paper : 

 briefly, that most species are in varying degrees iudigestil)le 

 and liable to be refused when the enemy's gastric activity 

 is insufficient to deal with them — that, therefore, there are 

 relatively few species that do not require to be distinguishable 

 at times from species that the enemy is at the moment 

 iiungry enough to digest. 



Would the explanation also apply to the eggs of birds? 

 occurred to me at first as an objection. 



That it might be found applicable to the coloration of 

 adult birds was rendered likely enough by the results of 

 Marshall's experiments already referred to. There was 

 no such evidence for eggs. Yet, working for some years 

 with insects, I was already able to perceive that there is a 

 close similarity between the phenomena of the coloration of 

 birds' eggs and those of the coloration of butterflies, in spite 

 of the fact that we have in the one case a generalized 

 pattern and in the other a definite one, and to feel that 

 whatever interpretation completely explained the one set 

 would quite likely be found to fit the other. I had also 

 met with eggs broken in the nest, not by the parents, yet 

 uneaten. And the diff'erence in flavour and consistency 

 between, for example, Fowls', Ducks', and Plovers' eggs, even 

 when cooked, suggested that at any rate a basis for possible 

 preference on the part of enemies might be present. These 

 and other considerations convinced me that the idea was at 

 least worth testing. 



I tested it in January and February 1913 on a lemur 

 (Galago crassicaudatus Geoff'r.) and a black rat. Attempts 

 to secure other egg-eating animals were unsuccessful. The 

 experiments carried out were sufficiently numerous and very 



