FEB 9 1893 



THE ENTOMOLOGIST. 



Vol. XXVL] JANUARY, 1893. [No. 356. 



EDITORIAL. 



It is with great pleasure that we have to announce that 

 Mr. Robert Adkin, F.E.S., who is ah-eady well known to our 

 readers, has kindly consented to act on the Reference Committee 

 of this Journal. 



THE CYANIDE-REACTION WITH YELLOW LEPIDOPTERA. 



By F. H. Perey Coste, B.Sc. (Lond.), F.C.S., F.L.S. 



The present article is condensed from a paper read before the 

 Linnean Society last June, and detailing an investigation into the 

 red colour produced by wet potassium cyanide on certain yellow 

 species of Lepidoptera. Referring my readers to my previous 

 articles in the 'Entomologist'* for an account of the earlier 

 stages of the work, I pass at once to describe the new results. 



Having succeeded in my attempt to redden C. ediisa and 

 O. rhamni by exposing them to the action of cyanide in a sloppy 

 condition, I next proceeded to test a number of yellow species in 

 order to determine whether this phenomenon was peculiar to 

 edusa and rhamni, or general among yellow species. I succeeded 

 in easily obtaining fine red blotches in Callidryas euhule, Terias 

 nise, T. rubella, T. nicippe, and (later) in G. cleopatra, Catopsilia 

 crocale, and C. catilla, the reaction being remarkably tine with 

 G. cleopatra, since nearly the whole wing assumed a blood-red 

 colour. 



In several of these experiments the fact was very noticeable 

 that there was, so to speak, a race between the solvent, and the 

 reddening, actions of the cyanide ; the more quickly that the 

 yellow was dissolved, obviously the less would be left to be 



* Vol. xxiv. pp. 163—167 (1891). 



ENTOM. JAN. 1893. B 



