3i6 COLOUR IN NATURE chap. 



forward some new facts of great interest in this 

 connection. Piepers opposes altogether the idea of 

 the action of Natural Selection in the matter, and 

 remarks that the idea that the phenomenon is main- 

 tained by the accruing practical profit to the organism 

 is one " essentially English." 



I. Mimicry. — As is well known, the doctrine of 

 mimicry among butterflies involves primarily the 

 hypothesis that birds are the great enemies of 

 diurnal butterflies, that certain families of butterflies, 

 notably the Heliconidse, the Danaidae, and the 

 Acrajidae, are not attacked by birds, and that there- 

 fore wherever these butterflies occur they are 

 mimicked by non- protected butterflies. Piepers 

 attacks the prime proposition that birds are the 

 great enemies of butterflies, and then discusses in 

 detail some of the so-called examples of mimicry. 



As to the first point, it is admitted on all hands 

 that the night-flying Lepidoptera are constantly eaten 

 by birds, but with regard to the diurnal forms the 

 question is different. Observations as to the actual 

 pursuit of butterflies by birds are exceedingly few, 

 although Bates and Wallace speak of finding scattered 

 wings in the forest. M. Piepers, during more than 

 thirty years' observation in India and the Malay, saw 

 one or two isolated cases only, and he quotes other 

 observers (Pryer, Skertchly, Scudder) as being equally 

 or more unfortunate. As a whole, he concludes that 

 although some birds may occasionally eat diurnal 

 butterflies, there is as yet no evidence of that habitual, 

 unvarying persecution which the theory of mimicry 

 demands — a conclusion which is somewhat surprising 

 to the outsider. 



