COLOUR IN LEPIDOPTERA. 19 



I still have to mention here a paper by J. A. D. in 

 Nature (Nr. 1544) headed » Evolution without Selection", 

 directed against me. As this article does not contain any- 

 thing but a personal attack without a single scientific 

 argument, I cannot respond to it in this periodical. I 

 tried to do so in » Nature", but the Editors, who had 

 several columns to spare for this attack, were not so cour- 

 teous as to open those columns to my answer too. 



The conclusion of all these investigations seems to me 

 to be a great deal more to the advantage of my hypothesis 

 than to the contrary, howsoever strange they may appear to 

 some people. And in fact I do not consider myself as beaten. 

 But those that intend to attack my theory seriously, will 

 certainly have to combat in the first place the phenomenon 

 denominated » Evolution of Colour", that I believe to have 

 established in the Sph{ngidae-ca.terTpi\\ars. If my observations 

 on this point are wrong, let it be demonstrated. Does any- 

 body know how to interpret them otherwise? Perhaps in 

 the way indicated in former years by Prof. E. B. Poulton? '). 

 Miss Newbegin from her partial chemical standpoint does 

 indeed think that explanation quite correct, but since I 

 have pointed out that the change of colour of these cater- 



and cannot therefore examine and compare the facts upon which my opinions 

 are hased. And I think she has not quite understood ray standpoint as to 

 Eimer's theory of «das Organische Wachsen". So at the end of her study she 

 says that I pretend to reject the basis of that theory and yet continually point 

 out facts clearly confirming it. This doubtless alludes to page 275 of ray paper, 

 where I say that I believe his theory ought to be absolutely rejected. However 

 what is said there has nothing whatever to do with Elmer's theory of »das 

 Organische Wachsen", but refers to his bands- and pattern theory. With the 

 first one I do agree pretty well on the whole. 



I met with more similar inadvertencies and of course they are narrowly 

 connected with the authoress' judgment of my study. But when she says that 

 my thesis of a hereditary stress ruling the colour-evolution does not explain the 

 cause of that phenomenon, she most certainly is quite right. About the ulti- 

 mate cause I have said little. Does this however attack the justness of my 

 observations as to this phenomenon and the importance of its existence? 



1) E. B. Poulton. The Essential Nature of the Colouring of Phytophagous 

 Larvae (and their Pupae); with an Account of some Experiments upon the 



Notes from the Leyden JMuseum , "Vol. XXII. 



