to limitations of the Mullerian Hypothesis of Mimicry. 139 



contrary, tliey will have been gradually evolved. We may 

 therefore expect to find at the present day species in a 

 transitional state, which, while possessing a certain degree 

 of distastefulness, still find it necessary to retain the 

 habits, or even the colouring, of edible forms. With this 

 proposition I entirely agree ; for it seems very probable 

 that such cases will occasionally be found. But I fail to 

 see that such an admission will justify a wholesale assump- 

 tion of moderate distastefulness throughout all the Pierinie, 

 for example ; and this is especially unwarranted in those 

 particular cases where experimental evidence points in an 

 opposite direction. 



Here another objection is likely to be raised against 

 me, for it will be argued that experimental evidence may 

 at times be very misleading. Again I am quite ready 

 to admit that there is much truth in this as a general 

 observation. Professor Poulton insisted very strongly 

 upon this view when commenting upon my experiments 

 (Trans. Ent. Soc. 1902). With reference to the eating of 

 Acrxinx by a ground hornbill, he says : " It has already 

 been pointed out that the acceptance of insects by insect- 

 ivorous animals in captivity is no proof of their normal 

 likes or dislikes in a wild state. Such acceptance only 

 proves what their action would be when they had been, 

 from some exceptional cause, kept without their normal 

 food in its usual quantity and variety " (/. c. p. 348). 

 Unfortunately the general criticism does not happen to 

 apply to the particular case. The bird was entirely 

 unconfined, and wandered at will searching for his food 

 just like his wild relatives on the next hill-side, with only 

 this exception : if insects, etc., were scarce, the wild birds 

 would have to go hungry or eat what they did not like, 

 while Colonel Bowker s bird always got additional food at 

 the house. The conditions of the experiment therefore 

 render it highly improbable that the hornbill was eating 

 insects which it would normally reject, and its whole 

 demeanour was quite at variance with such a supposition. 



Again, in reference to my experiments with baboons 

 the following criticism w^as made : " Considering what 

 has been already argued about insect-eating animals in 

 confinement, the acceptances (excluding the Hesperidm) 

 probably do not justify the conclusion that the Lepidoptera 

 were palatable, or that they would be sought for in the 

 wild state except under the stress of hunger " {I. c. p. 389). 



