104 Mr. C. F. M. Swynnerton on 



this list represents tlie order in which the objects comprising 

 it would be discarded as the bird filled up from emptiness to 

 repletion, or near it. Ten or eleven grades in all, and v/ith 

 further experimentation they would have been increased. 



The Babbler's preferences, in so far as they were ascertained, 

 stood in the following order: — (1) Termites; (2j Pyrameis ; 

 (3) Neptis and possibly Ilenotesia ; (4) Mycalesis campina ; 

 Yptldma, and the pleasautest grasshoppers would come here 

 or in (3), and Hamanumida, Precis, the ants, and the moth- 

 larva3 in or above that grade ; (5) Terias ; Belenois and the 

 young green Saturniid larvse here or higher; {6) Mylothris; 

 (7) Aletis, Danaida, and Acnea — with (6) and (7) would be 

 bracketed the unpleasanter gregarious moth-larvse and some 

 of the Phytophagous beetles, and with (5), (6), and (7) the 

 millipede, Arctiid larva, wasps, blister-beetles, and pupal 

 and imaginal ladybirds. The Babbler was more inclined to 

 eat the latter, and especially their larvse, than any of the 

 other birds, seeming to get rid of much of the juice, and 

 with it presumably some of its objectionable qualities, by 

 much rubbing. Vigorous rubbing was also used to exhaust 

 the pungent but volatile defence of the millipede in experi- 

 ment 564. The moth Spiting omorplia was much liked, 

 Ospryncliotus (the ichneumon) was placed high (an unusual 

 occurrence), certain strong-smelling bugs were also placed 

 high (by no means so unusual), C. cloantha was preferred to 

 C.Jiorella and P . angolanus, and the second-named butterfly 

 probably to the third. The unusually high placing of the 

 ants, the ichneumon, and the Coccintdid larvse suggest that 

 Crateropus is perhaps a specialized bird, and that it would 

 have been of great interest to pursue its general preferences 

 further. The resemblance of its butterfly preferences to 

 those of Lophoceros melanoleucus is marked. 



The preferences we have dealt with so far are the enforced 

 preferences of birds. These have to let pass an Acrcea or a 

 Coprid, let us say, because their digestion is insufficiently 

 vigorous to deal with the former or their strength to break 

 the latter. But there are two other kinds of preference — 

 the choice of the largest, and the turning of the whole atten- 



