42 Mr. F. Merrifield on the effects of artificial 



be useful to mention the names of some species on the 

 colouring of which I have not hitherto found any effect 

 produced by the pupal temperature. They are the 

 spring emergence of P. machaon and P. poclaliriiLs (both 

 from Southern Spain), 'Hiais pohjjcena, A. liaphia, D. 

 vimda, T. orhona {comes), and B. cijnthia. P. hrassicm 

 and P. rajxs are affected, but as yet I have seen no great 

 effect produced on them. I think the spring emergence 

 of ^. levana is affected, but, so far as my opportunities 

 have enabled me to judge, very slightly so. 



Effect of light. — It has been suggested to me by mem- 

 bers of this Society that light, especially about the time 

 of emergence, might influence colour. I have therefore 

 tried some experiments on the point. The first were 

 with some of the spring emergence of illustraria : 32 of 

 a healthy brood were on the 1st February divided as 

 nearly as might be between the two sexes, and placed in 

 lots of tw^o pairs each on the sill inside the window of a 

 rather large bedroom facing E.S.E., in which there was 

 always a small fire night and morning. They were at a 

 temperature generally ranging from about 46° to 57°, 

 rising sometimes to 63° during sunshine. The pupte 

 were protected from direct sunshine. Seven lots of four 

 pupfe each were placed in white jam-pots, their tops 

 covered respectively with glass — clear, purple, blue, 

 green, yellow, orange, and red ; while an eighth lot was 

 covered so as to be quite dark. Afterwards another lot 

 of four pupa3 from the same parents was similarly 

 exposed, with no light admitted but such as came through 

 a solution of bichromate of potash. Nearly all emerged 

 uncrippled between 8th March and 6th April. I can find 

 no appreciable difference between them in appearance. 



Afterwards I tried the following experiments with 

 B. cynthia : — On the 13th April, I took seven pupae out 

 of their cocoons, and laid them on the bare surface of 

 some cocoa-nut fibre at the bottom of a very large 

 flower-pot placed in a balcony facing E.S.E., covered 

 with a sheet of glass, and the pup[e protected from direct 

 sunshine. Seven others were treated in another flower- 

 pot, side by side, with the diti'erence that the pupae were 

 left in their cocoons, which were covered with tinfoil, 

 and were also provided with long caps of tinfoil, excluding 

 light, but capable of being pushed off" by the moths in 

 emerging, which happened. All the 14 emerged between 



