Adjustment of colour in vaoious -puj^i^, etc. 871 



Early in July last I happened to mention to Prof. 

 Poulton that I had then a considerable number of larvae of 

 P. macliaon which I had received from Germany, and at 

 his suggestion I experimented on some of those I had left 

 at this time, receiving much useful information from him 

 personally as well as from the very full record of his 

 experiments on other species, in the paper above referred 

 to, and in his subsequent paper in the Transactions of this 

 Society for 1892, pp. 293-487. 



The experiment thus begun gave rise to many other 

 experiments in which different species were employed. 

 The results were in large part displayed and an account 

 given of them at the meeting of this Society on October 

 5th, 1898 (Proc. Ent. Soc. Lond. 1898, pp. xxx— xxxi). 

 Professor Poulton was at the meeting and also showed the 

 results of some further experiments he had been making 

 in 1898 (Proc. Ent. Soc. /. c. pp. xxxii — xxxiii). The same 

 day I suggested to him that it would be usefid to arrange 

 the results of my experiments according to the standards of 

 colour which he had already published, and construct fresh 

 standards for the species with which he had experimented 

 but little or not at all. He approved the suggestion and 

 agreed to arrange the results accordingly, and also offered to 

 include the results of the experiments he had recently made. 



This memoir accordingly appears in our joint names. 

 The name or initials of the worker who conducted the 

 investigation will appear in the heading of each descrip- 

 tion. Professor Poulton is responsible for the new 

 standards of comparison and the tabulation of all the 

 pupae. In arranging the pupae, he allowed due weight to 

 the description of my results so far as I had made one. 



F. Merrifield. 



A few brief words are all that are necessary to form my 

 introduction to our joint paper ; inasmuch as Mr. Merrifield 

 has fully explained the circumstances under which it came 

 to be written. I was only too pleased to act upon his 

 suggestion, and thus to combine the record of our investi- 

 gations. It is more convenient in every way that there 

 should be a single complete account instead of two less 

 complete ones. The method adopted of placing the initials 

 of the writer after the title of each Section he has com- 

 municated makes our individual responsibility perfectly 

 clear. 



