THE FAERY YEAR 



There is the looper caterpillar of the swallow- 

 tailed moth, thought by some people to be the very 

 image of the elder twig on which it rests during the 

 day. In a book called <l Episodes in Insect Life," 

 published about sixty years ago, it is described as 

 " a withered-looking, stick-like creature, knobbed 

 and ringed and coloured, and even cracked after the 

 exact pattern of the browner stalks of its native tree." 

 Many other likenesses of the kind have appealed to 

 collectors and watchers of insects. 



We cannot overlook such facts as these, but how 

 is it that so many of these cases of matching and 

 mimicry are quite imperfect, even very slight ? If 

 they have been very slowly brought about by Nature 

 through a weeding-out process those caterpillars 

 least like their surroundings being killed off how 

 comes it that to-day, in spite of the terribly keen 

 search of the creature of prey, indifferent mimics 

 still live on and thrive ? Or if the process of selec- 

 tion be quicker than one might imagine, and sure, 

 how is it that the matching and mimicry are not far 

 more exact and deceptive in the bulk of cases than 

 we know them actually to be ? In some cases the 

 mimicry may be really wonderful ; but, as a rule, it 

 is no more than remarkable. Once assume that a 

 great, active law of matching and mimicry exists, and 

 then it is as though Nature were chary of going too 

 far with it, of over-legislating, lest her creatures of 

 prey should be starved out a policy of check and 

 counter-check and compromise a method of nicest 

 scale and balance. 

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