76 



THE BUTTERFLIES OF CEYLON, 



By 



Major N. Manders, r.a.m.c, f.z.s., f.e.s. 



{Read before the Bombay Natural History Society on 

 24th November 1904.) 



The Island of Ceylon has now been so thoroughly ransacked for 

 butterflies that assuredly very few species remain to be discovered, pro- 

 bably not more than half a dozen at the outside. Some general conclu- 

 sions regarding their origin and distribution may now be ventured on 

 and an analysis of the various species may be of some interest. 



Before doing so it may be as well to recall the chief geographical 

 features and climate of the Island, as it is on these two factors that the 

 variation of butterflies, to my mind, chiefly depend. Cape Comorin, at 

 the extreme end of the Indian Peninsula, almost reaches the 6th degree 

 North latitude and is opposite Puttalam in Ceylon, a small village not 

 more than eighty miles north of Colombo. The effect of this position 

 is that nearly two -thirds of the Island is sheltered, as it were, by the 

 Indian Peninsula, and this causes a remarkable contrast in the sheltered 

 and unsheltered portions of the Island. It will be noticed, further, that 

 the Hill districts of Ceylon are confined to the south-west portion of the 

 Island, so that the whole of the northern and eastern part is either shel- 

 tered by the mountains of India or those of Ceylon, and this causes a 

 very marked difference of climate in different parts of the Island. The 

 South-West monsoon passing up the East Coast of Africa is deflected off 

 the Island of Socotra across the Arabian Sea and divides into two cur. 

 rents, one of which strikes the Western Ghauts and the other the south- 

 west portion of Ceylon. That current which strikes the Indian Pen- 

 insula loses its moisture in the Western Ghauts and Anamallai and 

 Travancore Hills and reaches Ceylon north of Puttalam as a com- 

 paratively dry wind, and certainly a distinctly dry wind by the time 

 it reaches Trincomalee on the east of the Island. 



On the other hand, the mountains of the south-west portion of Ceylon 

 receive the full benefit of the South- West monsoon in the Hills and 

 comes to the South-East portion of the Island as a dry wind in a similar 

 manner as in the north. 



It will be noticed, therefore, that in the greater part of the Island 

 the South- West monsoon is a dry wind. On the other hand, the North- 

 East monsoon travelling over the Bay of Bengal reaches the northern 



