SATYIilNJE. ]51 



case in the Himalayas, insectivorous birds being especially numerous there durino-the 

 south-'n^est monsoon, when the ocelhite type of butterfly prevails." 



Mr. Doherty (J. A. S. Bengal, 1889, 118) gives us some subsequent observations 

 which he made on the Upper Assam frontier between August and December, and in 

 other parts of the East, stating that " The season was a very poor one, the cold 

 weather commencing earlier than usual. The dry-season, non-ocellate brood of Mycalesis, 

 Melanitis, Junonia, &c., appeared about the end of September, and none but rubbed 

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

 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 butterflies has 

 now received confirmation from various sources. In Eastern Java and the neighbour- 

 ing 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 SatyridiB 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 

 Nic^ville, who early adopted my views on this subject, some time ago reared 

 Mycalesis mineus from the eggs of M. visala, and has lately bred both 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 obtain- 

 ing both Melanitis Leda and ismene from the eggs of Leda by keeping 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 unusual 

 facility in captivity, and the larva feeds on young growing rice, which is always 

 obtainable. ... It was perhaps the general destruction of forests in the long- 

 settled parts of the East — India, China, Java — whether by the agency ofnatureorby 

 that of prehistoric man, that gave rise to seasonal dimorphism in the Satyrid^. In 

 the wet, dark woodland, their ocelli served them as a protection. Then came the 

 change; the country was partly deforested, and, instead of the former uniformly 

 damp climate, there was a long dry season in which the rank vegetation withered, 

 the sunlight entered everywhere, and the ocellate butterflies were rendered conspi- 

 cuous. Some species disappeared from the regions thus affected, while others lost 

 their ocelli and assumed the angular shape and dull neutral colouring of dry leaves, 

 and so survived. In the less variable climate of the equatorial regions, this has 

 rarely taken place, and generally only the ocellate broods are found there. And in 

 desert regions, instances may perhaps occur where the ocellate form has altogether 

 disappeared." 



