6 la Vanessa PohjchJuroH 



**I have read Mr. White's paper carefully through, and I 

 must say that I perfectly agree with Mr. Meldola. 



** The fact that the larva of V. Pohjchluros feeds upon elm, 

 whereas that of V. UrtiaE feeds upon nettle, w^ould naturally 

 lead me to look for a mutual progenitor of these and the 

 numerous allied species whose larvae should feed indiscrimi- 

 nately upon either the tree or the weed; this we find in 

 V. C-album ; therefore it is more probable that the group to 

 which the latter species belongs is the parent of both 

 V. Pohjchlorus and V. VrticcE than that the latter should be 

 derived from the former. 



'* The different races, or perhaps seasonal forms, of V. 

 C-alhum show considerable modifications in the outline of the 

 wing ; and an examination of foreign species shows that these 

 modifications may readily become permanent. 



*' I do not admit Mr. White's statement that food does not 

 produce variation. I have very little doubt, if he will try 

 the same experiment that I have done, his conviction will be 

 seriously shaken. Some years since my friend, Mr. Herbert 

 Goss, reared a number of singularly dark varieties of Odonestis 

 potatoria, and the only explanation for this burst of melanism 

 which he could suggest was, that he had been reckless as to 

 the species of grass upon which he fed the larvae. He sub- 

 sequently sent me some larvae, w^liich I fed upon different 

 grass every day, with the result that I did not rear a single 

 typical example, all being melanic and much dwarfed. When 

 I gave up collecting our British moths some years since I got 

 rid of my specimens with the exception of a single pair, 

 which are now in the general collection at the British 

 Museum. 



*' Mr. White says that his F. UrticcB is of the usual size, 

 but with the characters of Polychloros ; this description would 

 answer very well for F. Californica, and, considering the great 

 general resemblance between all the species of the group, the 

 case is not a very remarkable instance of reversion. 



" In a brood of about fifty T^ Urtic(E, reared by me, there 

 was a single very dark and small specimen which, although 

 not like V. PohjcJdorus, may have been a case of reversion to 



