68 Mr. C. F. M. Swynnerton on 



refused a fifth, though quite enger to take an Amavris. 

 B absolutely refused both Amauris and Tkinaida, but 



10 minutes later ate readily 3 A. albimaetdata, refusing a 

 fourth ; while A ate 2 Danaida, and persistently refused a 

 third, though still eager for Amauris. 



10 minutes later A ate readily 8 Danaidas, but refused the 

 ninth. B ate readily 4 Amauris albimacidata, then snatched 

 away and ate two Danaidas in succession that I was offering 

 A, and after this two more Amauris albimacidata, but re- 

 fused the next. 



15 minutes later A ate 3 Danaida and refused a fourth. 

 B absolutely refused A. alhimandafa . 



10 minutes later B still persisted in refusing that butterfly, 

 but A ate readily 7 Danaida and refused the eighth, B now 

 again refusing the Amauris. 



10 minutes later A ate one Danaida, but absolutely refused 

 a second. B refused A. albimacidata, but readily ate a 

 Danaida and wanted more, snatching persistently at the 

 one I now offered A. A ate one more Danaida after hesi- 

 tation, but persistently refused a second. 



10 minutes later — it was now in any case commencing to 

 get dark — both birds refused both butterflies. 



The last Danaida eaten was dead, the remainder having 

 been alive. A showed no ill-effects now or later from having 

 eaten 50 Danaida chrysippiis in little over two hours^ nor 

 did B from her 19 Amauris albimacidata, eaten during the 

 first hour and fifty minutes of that time. They digest rapidly, 

 and this, with the frequent intervals, enables them thus to 

 eat large numbers of relatively indigestible insects without 

 much overstepping the safety-limit. 



Analysis. A ate 10 Danaida and was ready to go on, and 

 10 minutes later ate 9 more, but then at last refused the 

 twentieth. But 10 minutes later he ate 4 more, refusing 

 the next, 15 minutes later 4 more again, refusing the next, 

 and after this only 2, refusing the third. However, 10 

 minutes after this partial rest he ate no less than 9, refusing 

 a tenth. These had some more lasting effect, for 15 minutes 

 later again he could only eat 3 — only a temporarj- effect 



