PROTECTIVE MIMICRY. 20 I 



originated by natural selection to be able to show this ; at the 

 same time the amount of protection given must be carefully 

 inquired into. There is too great haste in assuming that 

 because an insect is like a leaf or a twig it must be greatly 

 protected by this resemblance ; and that another is nauseous, 

 mid let alone on account of its warning coloration ; and where 

 experiments have been made, they have been very few.) 

 Hence insect-eating birds and reptiles must take a certain toll 

 of even the most warningly-coloured butterflies, before they 

 learn, by unpleasant experience, to associate bright colours and 

 a bitter taste. 



Now, if this be the case, it is clearly advantageous to the 

 insects that these depredations should not be confined to a 

 siugl species ; one species might be entirely obliterated, par- 

 ticularly if it was rare to begin with, by these experiments. 



On the other hand, if the necessary amount of destruction 

 were divided between, say half a dozen different species, the 

 loss to each species would be comparatively trifling. The 

 need for co-operation is quite evident. It will be noticed, how- 

 ever, that this explanation presupposes, not so much a general 

 association between warning colours and disagreeable taste 

 in the minds of birds, as a particular recognition of certain 

 patterns and colours, which huec to be learnt by rack bird, and 

 are not hereditary impressions. 



This is not altogether in accord with some of the experiments 

 given on page 1(34. If the reader will turn to that page, he 

 will find there recorded that certain birds objected strongly to 

 certain caterpillars, which they could not possibly have seen 

 before. 



Mr. Scudder has suggested a third way of explaining this 

 mimicry among mimicked species. There are, no doubt, 

 various degrees of distastefulness among disagreeably-flavoured 



