VALIDITY OF SOME FORMS OF MIMICRY. 741 



1 Papilio hector and 1 P. aristolochice ; it seemed a good deal 

 worried by the wings. Afterwards neglected M. ceylonica and 

 T. violm, but ate one wingless Eupla-a core. 



The conclusion we arrived at from the above experiments was 

 that butterflies were not its natural food, but that when hungry 

 it would eat them indiscriminately, and tliat the palatability or 

 otherwise of butterflies was of no account with this species of 

 bird. 



The dietary of Ceylon insectivorous birds is faii'ly well known, 

 and we are now in a position to discuss the cpiestions — Do tlie 

 birds of this island eat butterflies largely ? If so, do they eat them 

 in sufticient quantity to produce aiw form of mimicrj' ? and do 

 they show any discrimination in their attacks ? In other words, 

 can the terms palatable and unpalatable as applied to butterflies 

 be maintained. 



As regards the first question, it Avill be granted that there is 

 a gi'eater destruction of butterfly life than has hitherto been 

 supposed, and the following observation on a Bee-eater, though 

 necessarily a rough one, shows clearly that the destruction is 

 sufiiciently severe to produce mimiciy, provided of course that 

 the agents showed suflicient discriinination in their attacks. 



The road from Trincomali on the north-east coast to Anura.dha- 

 pura, runs through fifty-eight miles of thick forest which is cut 

 back some thirty paces on either side, thus afibrding a convenient 

 place for butterflies which avoid the dense jungle. Between the 

 hours of 9 A.M. and 10 a.m., I counted the number of butterflies 

 between the third and fourth milestones from Anuradhapura, and 

 they came to one hundred and ninety -five : the same day, in the 

 outskirts of the town I watched a Bee-eater feeding from 12.45 

 to 1 .45 P.M., and during this time it caught twenty insects ; on 

 only one occasion could I be certain that the capture was a butter- 

 fly, and this was undoubtedly Catopsilia pyranthi. The bird feeds 

 from about eleven o'clock till five. 



Motoinng between these two places I calculated roughly that 

 there was a pair of these birds to the mile*, and consequently 

 the whole of the butterflies along this road would be cleared off 

 in about a fortnight unless thej^ received an accession of strength. 

 The calculation is necessarily a rough one, but it gives a good 

 idea of the struggle for existence that is constantly going on. 

 This observation was made January 7th, 1909, at a time of year 

 when butterflies are less numerous than usual. 



The question whether discrimination is shown by birds in their 

 attacks on butterflies is of the greatest importance in mimicry, 

 and on the answer depends the fate of both Batesian and 

 Miillerian mimiciy. 



I do not attach much importance to the fact, curious though it is, 



* Bee-eaters are particularly fond of perching on telegraph-wires. 



