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THE CLIMATAL CHANGES OF MELANITIS LEDA. 



BY 

 LlEUT.-COL. N. MANDEES, F.Z.S., F.E.S. 



It is difficult, when writing on this fascinating subject, to refrain from indulg- 

 ing in. equally fascinating theories regarding the why and wherefore certain 

 species of butterflies vary according to the season of the year. In some cases, 

 particularly among African butterflies, these changes are truly wonderful, and it 

 is quite easy to understand why, when examining examples of seasonal variation 

 from that continent, so many insects now known to be the same species were 

 formerly regarded as distinct and were so described. My object, however, at 

 present is simply to record the facts I have observed with regard to one species 

 only, and my experiments connected with it. 



Th9 geaus Melankis has always been a puzzle both to systematic and field 

 entomologists. The extraordinary variations on the under surface to which all 

 its members are liable, have led to a most extensive synonymy, and the causes 

 which induce those variations are not yet by any means definitely settled. 

 I have hesitated whether to put on record the results of my experiments of the 

 last two years, but as it is a fascinating study, and one which, so far as I see, 

 will require observations and experiments far more extensive than any I can 

 hope to undertake, I give them in the hope that my failures will help others 

 to avoid many pitfalls and assist them to a right conclusion regarding a very 

 important biological problem. I am not concerned for the moment as to the 

 correct specific name of the insect under discussion, it is known in this island as 

 Melanilis leda, and as there is only one species, its identity can easily be estab- 

 lished. It is a species not found in India, but has the same habits and varies 

 in the same remarkable manner as the Indian species, I may recapitulate the 

 chief facts regarding its seasonal variation. The specimens found in the rains, 

 which are known as the " wet " season form, have well marked and well deve- 

 loped ocelli (I am referring in this paper to variation of the underside only), 

 the general ground colour being dark grey evenly and minutely striated with 

 darker grey. The " dry " season form varies in ground colour from a pale 

 rufous to a deep vinous purple, sometimes almost black, sometimes again pale 

 green with darker spots and blotches ; there is a partial or total disappearance 

 of the ocelli, usually these are represented by white dots in the pupils of the 

 ocelli, there is also a median line or fascia resembling in some respects the 

 midrib of a leaf ; but what is perhaps chiefly remarkable, especially in the 

 female, is a prolongation of the forewing below the apex, and a slighter prolon- 

 gation of the hindwing at the anal angle. Every variation (known as " Inter- 

 mediate ") can be found between the extreme forms. I hope Mr. Young will 

 figure sorne of these form3 when dealing with the Indian allies of this insect in 

 his papers on the Butterflies of the Indian Plains. If the seasonal forms were 

 confined to their respective seasons, the problem would be a simple one ; but 

 this is far from being the case. Mr. de Niceville many years ago bred both 



