220 



SCIENCE 



[N. S. Vol. XXXIII. No. 841 



forms were disliked by birds and other nat- 

 ural enemies; it was shown that young birds 

 did not instinctively reject these insects, but 

 that after having tried and found them 

 nauseous, they avoided them subsequently. 

 It was then not diificult to see that if an edible 

 species came to sufficiently resemble an in- 

 edible one it would be often taken for it and 

 so escape. At this point it was observed that 

 sometimes there were two or more butterflies 

 very much alike, but all inedible. Fritz 

 Miiller pointed out that there would be gain 

 in this, since the experience obtained in tast- 

 ing one might suffice to cause a bird to reject 

 all subsequently; whereas if they were all 

 alike, each would separately have to pay its 

 tribute to inexperience. Thus there were rec- 

 ognized two sorts of " mimicry," called the 

 Batesian and Miillerian, respectively. 



Examples of these phenomena have espe- 

 cially been observed in the tropics, where sub- 

 stantially the same conditions have existed for 

 long ages, and living things have had time to 

 develop some very nice adjustments and inter- 

 relations. In the volume just issued, Mr. 

 Eltringham has taken up the mimetic butter- 

 flies of Africa, and has covered the ground so 

 well that any reader may gain a good knowl- 

 edge of the main facts without access to a col- 

 lection of African specimens. There are given 

 no less than 176 excellent colored figures 

 illustrating the different species, varieties and 

 sexes, while in the text each one is discussed 

 at some length. There are also sufficient 

 bibliographical references. In addition to the 

 matter indicated by the title, there is a good 

 general discussion of the whole subject of 

 mimicry, and a summary of the evidence re- 

 lating to natural enemies. Thus Mr. Eltring- 

 ham's book may well serve as a guide to those 

 taking up the subject and will be found useful 

 in biological departments of universities, 

 where " mimicry " is discussed along with 

 other biological theories. 



A special chapter is devoted to objections 

 to the theory of mimicry, but those wishing to 

 see the strongest adverse arguments should 

 consult Professor R. C. Punnett's paper on 

 mimicry in Ceylon butterflies, recently (Sep- 



tember, 1910) published in Spolia Zeylanica, 

 Vol. VII. Professor Punnett spent two 

 months in Ceylon investigating some well- 

 known cases, and came to the conclusion (or 

 fortified a conclusion previously reached?) 

 that the phenomena should be explained in 

 quite another manner. Professor Punnett, 

 like Mr. Eltringham, gives us admirable col- 

 ored figures, and his discussion is most inter- 

 esting. Some of the points brought forward 

 are the following: (1) In Ceylon birds seem 

 not to be serious enemies of butterflies. The 

 chief enemies are apparently lizards and 

 Asilid flies, and these appear to lack discrimi- 

 nation. (Experiments with a lizard were 

 made.) (2) In various specified cases, the 

 " model " and " mimic " do not occupy the 

 same area to any extent, or the " model " is 

 scarce when the " mimic " is common, a con- 

 dition irreconcilable with the Batesian theory. 

 (3) The resemblance is often imperfect, and 

 when the flight of the insect is different it 

 seems unlikely that they should be confused. 

 Against evidence of this sort may be placed 

 the abundant data of Wallace, Marshall, 

 Trimen and others, who have spent long years 

 in the tropics, instead of a short two months. 

 It may be reasonably urged, however, that if 

 in only a few cases it can be demonstrated that 

 " mimicry " has a meaning quite different 

 from that assigned by Bates and Miiller, 

 serious suspicion is thrown on the whole 

 theory or group of theories. Professor Pun- 

 nett, long associated with Professor Bateson, 

 is of course well known as an ardent Men- 

 delian, and it is not a surprise to find at the 

 end of his paper a Mendelian interpretation 

 of mimicry. As he states, breeding experi- 

 ments are urgently required, but judging from 

 the classic experiments of Dpncaster on 

 Abraxas, he formulates an hypothesis to ac- 

 count for the polymorphism of mimetic 

 Papilio in Ceylon. We can not take the space 

 here to copy his tables, but the results he gets 

 appear to coincide with the facts. Incident- 

 ally he cites the case of Colias edusa, in 

 which the pale helice form of female, crossed 

 with a normal male (necessarily so, as helice 

 occurs only in the female) gave females of 



