MELANOCHROISM IN BHITISH LEPIPOPTERA. 223 



felt, in the species affected by sucli environment. — J. W. Tutt. 

 July 23rd, 1893. 



Mr. Tutt in his interesting comments on my short paper, p. 198 of 

 the Entomologist'' s Record, speaking of Indian dimorphic butterflies, 

 says, " that moisture can so unsettle, as it were, the normal constitution 

 of the larva that its natural hereditary tendency to produce a certain 

 form is overcome, and another form is produced in its place." I take 

 it that seasonal dimorphism is of yearly occurrence, and the question 

 comes up, whether we are entitled to assume, as Mr. Tutt does, that 

 the " dry " dimorphic form is the " normal " one, produced by the 

 " natural hereditary tendency " of the species. Is it not rather pro- 

 bable that the wet form is the older and therefore " normal " and that 

 the increasing dryness of the seasons has gradually produced the 

 variation ? If we connect melanochroism and these other phenomena 

 of variation with the former appearance of the species, the present 

 climatic environment must be closely studied, and some conclusion as 

 to the former climate must be reached. That butterflies maintain their 

 general appearance with a modern survival of their older normal en- 

 vironment is shown by the history of the North American Oeneis 

 semidea, which maintains itself on tlie summit of Mount Washington 

 and whose probable past geological story I have related in my paper 

 entitled : " A Colony of Butterflies," in the American Journal of Science 

 and Art. 



I think, then, that " wet and dark " conditions may produce a relapse 

 Ijy reversion to an older form of the species, and that there is also a 

 general probability that our butterflies are, as a whole, more brightly 

 coloured and lighter coloured to-day, than they or their ancestors, say 

 in the Carboniferous epoch, or in any Preglacial period, when they 

 were more generally exposed to a damp and dark environment. 



In concluding my present slight and tentative series of reflections 

 upon the subject of Melanochroism, I may take occasion to thank Mr. 

 Tutt for giving them a place, as well as to express my sense of the 

 scientific value of his work and of the use and importance of the 

 Entomologist's Record in disseminating necessary information and 

 stimulating enquiry in these matters. — A. E. Geote, M.A. Bremen, 

 Germany. 



I was not aware that I considered the " dry season " form the older 

 one, and at least did not mean to assume it to be so, in my remarks. 

 All I wished to sviggest was, that in a species with two ordinary and 

 so far normal forms, constant in the time of their occurrence and 

 different in appearance, changed conditions were capable of producing 

 either form contrary to that which would be 23roduced by nature, and 

 thus far, at least, we are able to prove that external conditions are 

 capable of acting on the larva? and producing variation. I only used 

 the term " normal " as meaning that the dry season form was normal 

 in the dry season, and the wet season form normal in the wet season. 

 I should call the wet season form abnormal, if developed in the dry 

 season and vice versa. I agree with Mr. Grote, that in some instances 

 the dark form is probably the older, but not always so. Each case 

 must be considered on its merits. — J. W. Tutt. July, 1893. 



