Adjustment of colour in various pupse, etc. 381 



coloured backgrounds that iu most cases f\^^f'^^^^.^; 

 hut I thoucrht it eminently desirable that the exlubition 

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

 to law independently, their own conclusions. I supple- 

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

 ment ^^'i^'^'^ ' • ^^ts As general results it will be 

 course ot my expeumenib. xxo » r^nn-p of P 



enouo-h perhaps here to say that the 16 pupse ot r 

 mZtoJon the black paper-covered sticks and on dark 

 iraturTsUcks are all ,4 with the exception of one 

 which is yellow-green; those that were ^^ ^^/^rong light 

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

 lelolgLn; that of the 9 on white paper 1 is ^rey 

 fnd thi other 8 all yellotv-greeii or light grey with a 

 '^en^sh tincre; that of the 6 on yellow P=^Per 2 ^re 

 f^^-grei^d the other 4 yello^o-green ; and that of 

 the 4 on orange paper all are yellow-green 



TheseresuUs seem to me clearly to prove the susceptibihty 



°'Thr;tr-of F. mackao. on the othei- coloured sur- 

 roundirl^'employed did not give such definite results; 

 particulars are given in the next section. 



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



The DUDse were compared May 2nd, 1899. 

 The various conditions to which the larv* of P. maehac,^^ 

 weresu4cted will be considered in the same order as that 

 adopted by Mr. Merrifield on p. 380. 



(1) BLACK PAPER. («) In strong light. 

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



1 pupl^ fixed' to black tissue-paper, was intermediate 

 between dark and light grey (2 a 6). 



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

 was qrey probably similar to the ast. 



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

 probably similar to the last. 



5 



(b) In fair light. 

 The single pupa (dead and discoloured) was fixed to 

 bllkU. ^It .LVpossible topWe ^t w.thany ce„ 

 but the appearance suggested that it Had oeeu y 

 green. 



