Blnh in Relation to their Prey. 91 



574. April 10. — In most cases the insects in this experi- 

 ment were pulled about a good deal before being finally 

 swallowed or abandoned. 



The bird tasted and rejected an Epilaclina, but ate a 

 Mylahris ontlata and a wingless Acraa natalica, rejected 

 an Acraa area ? and a second A. natalica, ate a " frog- 

 hopper," rejected a large grej^ millipede with almond 

 smell; readily ate four small bright orange-coloured centi- 

 pedes, but refused to touch any more, rejected a beetle with 

 protective fluid (not identified), but readily ate a Belenois 

 severina with wings. 



Concluding Discussion. 



We are perhaps inclined to take somewhat too much for 

 granted a bird's relations to its prey. We shoot, saj^ a 

 Puff-back Shrike and find in its stomach two wasps, the 

 fragments of a Coprid beetle, and a Precis butterfly. We 

 record the bare fact in our next paper, but otherwise think 

 no more about it. Yet it would be most interesting to 

 enquire whether the above insects represent its normal food 

 or were only eaten under temporary stress of hunger ; to 

 know just how that Puff-back Shrike went about to circum- 

 vent the stings of the wasps, to break up the hard cliitin of 

 the beetle, and to capture so wary a butterfly ; and whether 

 other species of birds do these things in the same way or by 

 other methods. It would be interesting, also, to notice that 

 neither the wasps, the Coprid, nor the butterfly were about 

 in large numbers, yet insects that were abundant were not 

 represented in the bird's stomach. Why ? And, if we 

 decide that there must be some repugnance to, or fear of, or 

 inability to catch or deal with, these more obvious insects, in 

 virtue of what limitations on the bird's part does it exist, 

 and how did the bird learn to avoid them ? And so on. 



Methods of attack. — That some species of prey have special 

 defences that other species lack will hardly be denied, and 

 it is open to a bird to deal with them (1) by employino- 

 special methods of overcoming the defence in question, or 

 (2) by avoiding its possessor and exhibiting a preference 



