VALIDITY OF SOME FORMS OF MIMICRY. 731 



buttei-fly to my best belief the bird Jias taken since my previous 

 letter on the svibject. The bird is I'are here .... We liave had 

 no ilights of the yellow and white Catopsilias this year — so no 

 wings about — the Appias victims were mostly the white forms cJ 

 and $." 



7. The Roller' and Butter/Jies. 



I am unable to add much regai'ding this bird's dietaiy. It is 

 found only in the dry northern districts and is uncommon. In the 

 plains of India it is a familiar occupant of the telegraph-wire, and 

 I have often seen it chasing and no doubt catching various insects 

 from such a perch. I have no doubt it catches butterflies, and 

 more than once am sure I have seen it do so, tliougli I am unable 

 to name the species captured. Judging by its very varied menu, 

 I have little doubt that it pays little heed to the species it 

 manages to catch, but of this I have no dii'ect evidence. 



8. Bee-eaters and Butterflies. 



Mr. Fred. Lewis, a well-known ornithologist, writes: — " Colombo, 



8.11.09 I have noticed Swinhoe's Bee-eater in particular 



hawking after the common so-called ' Adam's Peak butterfly ' 

 {^CatopsiVa and App'as\ and it appears to prefer the white one to 

 the lai-gei' yellow fly. It does not, so far as I am aware, take any 

 of the large brown buttei-flies often to be found with the above 

 named. I have watched the bird when quite a selection of flies 

 could be made, but beyond taking the white and an occasional 

 yellow, I have never seen it feed on others. I am not prepared to 

 say, however, that the Bee-eater does not eat any other butterflies 

 than the two mentioned. 



" Our common black King-Crow appears to select the same flies, 

 taking them on the wing in the same way as the Bee-eater. 

 Swallows do not, so far as my observations go, ever touch any 

 butterflies. 



" It is remarkable, however, on such occasions as one finds in the 

 dry zone, when vast masses of these 'Peak' whites and yellows 

 congregate round some wet pool or damp ground, that King-Crows 

 are not found taking the opportunity of a ' squai-e feed.' I infer 

 therefrom that the butterfly is only a ' side dish ' and not a 

 regular item of food. . . I cannot recall an instance of young birds 

 being fed with butterflies. I suspect the difficulty of swallowing 

 the wings is the reason, for I cannot say I have ever foiuid small 

 nestlings with anything so difficult of mastication in their 

 nest. . . ." 



In another letter Mr. Cave writes : — 



" Belvedere, Colombo, 



5th March, 1911. 



" In reply to your letter I am sorry to .say I have nothing 

 fiirthei'to report on the subject of the capturing of butterflies by 



