148 
LEPID OP TEE A INDIO A . 
In the Journ. Asiat. Soc. Bengal, 1885, p. 39, Mr, de Niceville farther says, 
ff< The constancy of this phenomenon is such that I cannot help thinking there must 
be some physical reason for it,—can it be a protective one ? The difference in the 
garb of the surrounding vegetation makes it little remarkable that a change should 
be found in the coloration of the butterflies of the two seasons, but it is difficult to 
see why this change should show itself in the obliteration or development of ocelli. 
The only hypothesis which I can suggest is, that during the rains the density of 
the vegetation is such that the butterflies can easily hide their conspicuous ocelli, 
while in the cold and dry seasons the ocelli, easily seen through the scantily-clothed 
jungle, would render the butterflies an easy prey to their inveterate enemies the 
birds, lizards, and insectivorous insects ; so that the ocellation being a cause of 
danger would have a worse chance of survival, and consequently would be gradually 
wiped out by a process of a survival of the fittest, the fittest in this case being the 
least gaudily-marked individuals. Were this the case, however, the non-marked 
forms would certainly survive during the rains, for their homeliness of coloration, 
though no longer absolutely essential, would still give them an advantage over their 
ocellated brethren, unless indeed the ocelli are preserved by sexual selection at 
this time when the struggle for bare existence is not so keen as at other seasons.” 
In a subsequent paper (Journ. Asiat. Soc. Bengal, 1886, p. 229), Mr. de Nice vilie 
gives the life history of certain species of Calcutta Satyrinse, of the genera Mycalesis , 
Ypthima , and Melanitis , and states that he has “ been able to prove by breeding 
direct from the egg, that the extraordinary seasonal dimorphism which he had 
previously suspected to occur does actually exist,” and gives the details of the 
rearing of the species therein described, which, up to that date, he had suceeeded in 
obtaining for breeding. The life history of these dimorphic species will be found 
described under the genera above referred to. 
Later on Mr. de Niceville writes (Journ. Asiat. Soc. Bengal, 1888, 273), “ With 
regard to many of the Indian Satyrinse, they are divided into two strongly-marked 
well-defined groups, ‘which I have designated dry and wet-season forms respectively. 
These forms prevail during their respective seasons, but are by no means strictly 
confined to them. For instance, it is a common occurrence in India to have what is 
called a s break in the rains/ when for many successive days the weather is some¬ 
what similar to that obtaining in the dry season. It may be noted that the 
Calcutta year is roughly divisible into a cold season, extending from the middle of 
October to end of March; a hot season, extending from April to middle of June; 
and a wet season or rains, from the middle of J une to the middle of October. Any 
larvm turning to pupae during a c break 5 would almost certainly, though they 
would emerge perhaps a week afterwards in a deluge of rain, be of the dry season 
form. Similarly, during the dry season, dry season forms prevail, but, should a 
