14 THE EVOLUTION OF 



regard forms but colours, while several facts mentioned 

 by myself and others met with by Dr. v. Bemmelen and 

 Dr. Grafin von Linden, indicate that colours showing them- 

 selves within the skin of the pupa, are sometimes altered 

 by their coming into contact with light or air, and so 

 probably those same colours may at an earlier period also 

 have been different in the full-grown animal from what 

 üntogenetically is found to-day. Also the possibility of 

 other influences acting on the insect of to-day, even though 

 not yet full-grown, cannot be denied, influences different 

 from those to which its ancestors were exposed during the 

 phylogenesis, that may cause such differences. Considering 

 all this, it surely would be presumptuous to attach too 

 much importance as decisive in itself to the results of such 

 investigations, but still they remain facts of great signifi- 

 cance which one have to be reckoned with. 



Dr. Grafin von Linden has now been investigating in 

 that manner 5 butterflies viz. Papilio Machqon L., Fapilio 

 Podalirius L., Thais Folyxena Schiff., Vanessa urticae L. and 

 Vanessa Levana L., and she has done it pretty carefully. 

 Unfortunately, however, there lies, if I may say so here, 

 spread over these investigations a veil that will have to be 

 removed before they are fit for use. Quite infatuated by the 

 assertions of the late Prof. Dr. Eimer, in whose last work 

 she has, as I believe, taken a large part as his assistant, 

 she adopts all his views in their full consequences, among 

 which views there are two that I most decidedly must 

 reject, though being of the same opinion as Dr. Eimer on 

 many points. Now these two views happen to be of the 

 greatest importance concerning the subject treated by me. 

 They are firstly Dr. Elmer's well-known bands-and-spots- 

 theory and secondly one in which the form of the colour 

 spots on the wings of butterflies is considered as a thing 

 by itself and independent of the colour. Leaving alone now 

 the value of his theory as to the higher animals — though 

 that has been also lately contradicted by H. Meerwarth 

 with regard to the changes in the colour-pattern of bird- 

 Notes from the Leyden Museuin, Vol. X.X1I. 



