IS VANESSA POLYCHLOROS THE PROTOTYPE OF V. URTICA ? 173 



frequently happens, have been more or less preserved down to 

 the present time. Poh/chloros, Xantliomelas, Urticce, kc, are thus 

 true blood-relations, and, in accordance with the laws of heredity, 

 it is not therefore surprising, although extremely interesting, that 

 we should find one of these species occasionally giving rise to a 

 variety resembling an allied form. If, therefore, Mr. White means 

 to ask whether Polijchloros is the progenitor of Urticre on the 

 strength of his having obtained a variety of the latter resembling 

 the former, he (the President) would be inclined to answer that 

 the two species under consideration, with their congeneric forms, 

 had all descended from a common ancestor, and that the variety 

 in question was a case of reversion to this ancestral type. 



In illustration of the foregoing remarks the President ex- 

 hibited specimens of Urticce Sbiid Polijchloros, with the intermediate 

 North Indian V. CasJimirensis, and, as a parallel case, Piframeis 

 Atalanta and Cardui, with the intermediate P. CalUrho?, likewise 

 from N. India. 



Mr. A. G. Butler, F.L.S., F.Z.S., of the Zoological Department, 

 British Museum, has kindly furnished the Editor of the Trans- 

 actions with the following valuable observations on the above : — 



" 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. Polycliloros feeds upon elm, 

 whereas that of V. Urticce feeds upon nettle, would naturally lead 

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

 allied species whose larvae should feed indiscriminately upon 

 either the tree or the weed ; this we find in V. C- Album; therefore 

 it is more probable that the group to wdiich the latter species 

 belongs is the parent of both V. Polychloros and V. Urticce than 

 that the latter should be derived from the former. 



" The different races, or perhaps seasonal forms, of V. C -Album 

 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 Gosse, reared 

 a number of singularly dark varieties of Oclonestis potatorici, and 



