100 Mr. C. F. M. Svvynnerton on 



are discarded, then the AcrfenicT, then Mylotliris, then 

 Belenois, Terias, and some Lycfenids, then Mycalesis, Nejyiis, 

 a skipper or two, and various mimetic genera in Nymphalinae, 

 Pierince, and Lycsenidse, then Eurytela and Lenceronia, next 

 certain Papilios, and after them Precis, &c. Finally (if the 

 bird is capable of easily swallowing or reducing it), Chara.xes; 

 also some skippers. These would in most cases be eaten 

 nearly to repletion-point, but the average bird will still find 

 room for one or two such Noctuids as the Spliingomorplia of 

 the above experiments, while in birds that specialize in some 

 one order — as a Drongo in Diptera — several grades of that 

 order will often still intervene between the rejection of the 

 pleasantest insects of the remaining orders (including, it may 

 be, butterflies) and actual repletion-point. 



As well as these more general "specialists" and birds — 

 such as Hornbills — that are indiscriminating up to (but 

 not beyond) a certain point, we have yet another 

 class — the specialists in some one family or subfamily of 

 highly nauseous insects. I believe that our common Bulbul 

 [Pycnonotus layardi) is to some extent specialized to digest 

 Danaines, the individuals on which I have best tested them 

 placing them as high as Mycalesis ; and it seems probable 

 that the Ashy Wood-Swallow of India {Artamiis fvscus) is 

 even further specialized in the same direction *. That this 

 specialization of the digestion in a particular direction (if I 

 am right in believing it to be present) has perhaps been ac- 

 companied by loss of power in another direction is suggested 

 by the fact that my Bulbuls, that placed Danainse thus rela- 

 tively high, placed Pierinse generally quite unusually low. 

 The transposition of these two groups constitutes the greatest 

 divergence from normal tastes that I have come across, but, 

 while the order I have indicated above is generally held to, 

 small differences of taste, small transpositions of contiguous 



* There are probably few birds that are not specialists, and so indis- 

 criminating, in one direction or another. There would also seem to be 

 a gradation between the more usual birds which in most things dis- 

 criminate from the outset and those, like Lophoceros, which commence 

 late. 



