Adjustment of colour in various pupie, etc. 381 



coloured backgrounds that in most cases adhered to them ; 

 but I thought it eminently desirable that the exhibition 

 should supply its own evidence, so as to enable all who see 

 it to draw, independently, their own conclusions. I supple- 

 ment it, however, with all the other pupae obtained in the 

 course of my experiments. As general results it will be 

 enough perhaps here to say that the 16 pupae of P. 

 machaon on the black paper-covered sticks and on dark 

 natural sticks are all grey, with the exception of one, 

 which is yellow-fjrcen ; those that were in a strong light 

 are very dark ; that of the 4 on carrot-tops all are 

 yclloiv-grecn ; that of the 9 on white paper 1 is grey 

 and the other 8 all yellmv-green or light grey with a 

 greenish tinge; that of the 6 on yellow paper 2 are 

 greenish-grey and the other 4 yellow-green ; and that of 

 the 4 on orange paper all are yellow-green. 



These results seem to me clearly to prove the susceptibility 

 of P. machaon. 



The pupaB of P. machaon on the other coloured sur- 

 roundings employed did not give such definite results ; 

 particulars are given in the next section. 



4. Results of the above Experiments. (E. B. P.) 



The pupse were compared May 2nd, 1899. 



The various conditions to which the larvaB of P. machaon 

 were subjected will be considered in the same order as that 

 adopted by Mr. Merrifield on p. 380. 



(1) BLACK PAPER, (rt) Pti strong light. 



2 pupse, fixed to black tissue-paper, were very dark 



grey (2 h). 

 1 pupa, fixed to black tissue-paper, was intermediate 



between dark and light grey (2 a, h). 

 1 pupa, fixed to black tissue-paper, had emerged, and 



was grey, probably similar to the last. 

 1 pupa, fixed to black net, was dead, and was grey, 



probably similar to the last. 

 5 



(6) In fair light. 



The single pupa (dead and discoloured) was fixed to 

 black net. It was impossible to place it with any certainty, 

 but the appearance suggested that it had been yellow- 

 green. 



