118 



W. Dolierty — Notes on Assam Butterflies. 



[No. 1, 



V. — Notes on Assam Suttorflies. — By William Doheett, Cincinnati, 

 U. 8. A, Ommnimicated hy the Supeeintendent of the Indian 

 Museum. 



[Received and Bead Jannary 2ud, 1889.] 

 (With Plate X.) 



A collection of butterflies made on the Upper Assam frontier be- 

 tween August and December, afforded material for the following notes. 

 The specimens were taken partly in the hills beyond Margherita, on 

 the border of the independent Naga country, fifty miles due south of 

 Sadiya and the Brahmaputra, and partly on the Dibang and Dikrang 

 rivers north of Sadiya. The season was a very poor one, the cold 

 weather commencing earlier than usual. The number of species taken 

 was so small, and some groups were so poorly represented, that I have 

 thought it best to postpone publishing a list of tlio butterflies of the 

 district till after my return there next spring. 



The dry-season, non-ocellate brood of Mycalesis, Melanitis, Juuonia, 

 etc., appeared about the end of September, and none but rubbed and 

 ragged individuals of the wet-season brood were seen flying after that 

 date. jEmona amatlmsia, a morphid, turned out to be also dimorphic, 

 as indeed might have been expected. My theory of the effect of drought 

 and humidity (somewhat like that of heat and cold on certain European 

 species) on the shape and ocellation of these buttei'flies has now re- 

 ceived confirmation from various sources. In Eastern Java and the 

 neighbouring islands of Sumba, Sambawa, and Timor, the seasons are 

 the reverse of those in India, the winter months — December, January 

 and February — being the rainy ones. I found the broods of the Satyridm 

 similarly reversed there, the wet-season form coming out late in the 

 autumn, and the dry-season one in the spring. This is of course only 

 indirect evidence, but direct evidence has not been wanting. Mr. de 

 Niceville, who early adopted my views on this subject, some time ago 

 reared Mycalesis mineus from the eggs of M. visala and has lately bi'ed 

 hoth forms of Melanitis leda under natural conditions from the eggs of 

 the ocellate one. This, however, took place at the time of the change 

 of monsoon. At any other time it must be very unusual for both forms 

 to come from the same parent. Two years ago in the early part of the 

 dry season in the island of Sambawa, I succeeded in obtaining both 

 Melanitis leda (determinata) and ismene from the eggs of leda by keep- 

 ing a wet sponge in the box in which the former species was reared. 

 I particularly recommend this experiment to naturalists living in the 

 East, as Melanitis lays its eggs with nuusual facility in captivity, and tJie 

 larva feeds on young growing rice, which is always obtainable. My 



