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Recent Literature. I April 



nated with Mr. H. W. Bates, the well-known English naturalist who 

 spent so many years on the Amazon in South America. It was suggested 

 by his finding that a certain group of butterflies (Heliconidre), conspicu- 

 ously banded with yellow and black, were provided with certain glands 

 which secrete a nauseating fluid, supposed to render them unpalatable to 

 birds. In the same situations were also found similarly colored butterflies 

 belonging to another family ' (Pieridae), which so closely resembled the 

 others in shape and markings as to be easily mistaken for them, but which 

 were unprovided with the scent-secreting glands, and were thus unpro- 

 tected from attacks from birds. This resemblance it was thought was 

 brought about by natural selection for the protection of the edible butter- 

 flies through the birds mistaking them for the inedible kind. Other cases 

 of mimicry among a great variety of insects have since been pointed out, 

 and the theory of protective mimicry has secured many adherents. A 

 close scrutiny of these alleged cases, however, shows that in many 

 instances, and to a considerable extent, 'protection fails to protect.' Mr. 

 Beddard gives the evidence in favor of mimicry at some length, inter- 

 spersed with some rebutting comment, and then discusses the objections 

 to the theory. The discussion is too long to be followed here, and the 

 objections too numerous even for recapitulation. One is that resemblances 

 occur between animals inhabiting widely separated areas which are so 

 close that if the same forms were found together one would be considered 

 as a case of mimicry of the other. Again resemblances occur between 

 distantly related forms found in the same country in which neither has 

 any special means of protection, and hence the 'mimicry' is without any 

 protective effect. Again, cases occur where the resemblance is a positive 

 disadvantage to the mimicker. Many special cases, as of flies mimicking 

 bees, spiders mimicking ants, etc., are dealt with separately, and the 

 objections in each case seem fairly conclusive. In commenting upon 

 the rarity of even alleged cases of mimicry among mammals, Mr. Beddard 

 considers that this fact is not remarkable, when we consider how few the 

 total number of mammals is when compared with insects, and that out of 

 the vast assemblage of the latter "it would be strange if there were not 

 many cases of accidental resemblance; and there are many such" (p. 237). 

 In 'Chapter VI. Sexual Coloration,' Mr. Beddard appears to wholly 

 reject Mr. Darwin's much admired theory of 'Sexual Selection,' and quotes 

 at length Mr. Wallace's rednctio ad absiirdum, which, as illustrating the 

 view of an ultra natural selectionist, may well be here transcribed : 'Nat- 

 ural selection .... acts perpetually and on an enormous scale in 

 weeding out the 'unfit' at every stage of existence, and preserving only 

 those which are in all respects the very best. . . . Now this extremely 

 rigid action of natural selection must render any attempt to select mere 

 ornament utterly nugatory, unless the most ornamented always coincide 

 with 'the fittest' in every other respect; while if they do so coincide, then 

 any selection of ornament is altogether superfluous. If the most brightly 

 coloured and fullest plumaged males are not the most healthy and vig- 



