166 THE ENTOMOLOGIST. 



merited next. I succeeded in obtaining red spots, but not to any 

 great extent. 



After this, as will be readily understood, 1 hasten to retract 

 in toto my previous scepticism on this subject, and to recant any 

 or every disparaging remark that I may have uttered on the 

 possibility of converting yellow to red artificially ; and at the same 

 time I have the very pleasant duty of expressing my sense of the 

 heavy indebtedness under which I lie to Mr. Cockerell for having 

 drawn my attention to Mr. Edwards' statement, and made the 

 further suggestions concerning wet cyanide. My own experiments 

 having been originally planned entirely with solutions, it is highly 

 improbable that I should ever have tried a solid, or rather sloppy 

 solid, reagent but for Mr. Cockerell's tenacity in backing up his 

 authority ; and therefore I feel that, but for this, I should in all 

 probability have missed the interesting prospect opened up by 

 these new results. At the same time, I may point out that 

 there is reason for surprise at the solution of cyanide failing to 

 produce a red ; for even the wet cyanide exerts a considerable 

 solvent effect on the pigment, and in the case of the solution — as 

 my readers already know — such solvent action is rapid and 

 complete : under such circumstances there was obviously no time 

 or room for the reddening. 



With regard to the new field thus opened out for work, I can 

 promise my readers that it shall be neither neglected nor under- 

 valued ; the whole question must be thoroughly and carefully 

 worked out, and already sets of experiments are in progress, and 

 others planned, to this end. Doubtless, before very long, the 

 ' Entomologist ' will hear from me on this subject. 



In conclusion, I seem bound to say a word as to the bearings 

 of this discovery on my previous interpretations. It will, of 

 course, be understood that it is impossible to make any definite 

 statement, scarcely even to hazard a provisional explanation, on 

 the strength of two or three experiments. However, at present I 

 can see nothing here inconsistent with my theories on these 

 pigments, but, on the contrary, it looks not unlike a confirmation 

 from another side of my conclusions, while especially one may 

 hope that some more definite light may be thrown on the 

 phenomenon, of which an explanation was offered at the con- 

 clusion of Subsection F. The statement, however, that no 

 progressive metamorphosis can be effected must, of course, go ; 

 but, barring this, I think it will be found that there is nothing in 

 these fresh results incompatible with the views expressed on 

 pp. 370, 371, but rather we have here an ascending confirmation 

 of explanations founded originally on descending experiments. 

 The very uniqueness of (solid) cyanide as a reagent confirms the 

 view, that in all other cases we have retrogressive results, — results 

 wrought by those same reagents which we know to retrogressively 

 affect natural reds. 



