I8£^a] L, de '^iceYille— List of the Butterflies of Ceylon. 173 



in the North-East monsoon when very heavy rain falls for a very limited 

 period. Butterfly life in this region seems to be dependent very largely 

 on the rainfall, a certain amount of moisture being required to bring the 

 pup^ to emergence. On studying the list of butterflies it will be ob- 

 served — which indeed would naturally be expected — that the very great 

 majority of Ceylonese butterflies occur also in South India, or are very 

 closely related forms, and no doubt the butterfly fauna of Ceylon has 

 been almost entirely derived from Southern India. There is very little 

 evidence of any connection, with the Malayan region ; indeed, this 

 evidence is confined, as far as we know, to three species only, viz.y 

 JDanais exprpmpta, Butler, Euploea cortts, Fabricius, and Elymnias 

 singhala, Moore. D. exp'ompta is no doubt a local race of D. similis, 

 Linnseus, a Chinese species, and E. cams is related to E. castlenaui, 

 Felder, a Wicobarese and Malayan species. It is noteworthy that 

 these two species belong to a highly protected group and are very 

 tenacious of life. One might hazard the conjecture that the ancestors 

 of these species were carried hither by favourable winds from the 

 Malayan coast, succeeded in establishing themselves, and formed 

 local races. E. singhala is very closely akin to E. panthera, Fabricius, 

 (=E. lutescenSf Butler,) also a Malayan species, audit is remarkable that 

 its one locality almost is the Peradeniya Botanical Grardens, which con- 

 tains numerous Malayan Palmacese (on which the larva feeds) received 

 from that part of the world. The butterflies found only in Ceylon 

 otherwise than local forms are very few indeed. Danais taprolana, Felder, 

 is undoubtedly the most striking as it is a common and handsome insect. 

 The most interesting butterfly in Ceylon is, probably, Lethe dynsate, 

 Hewitson, as it has no allies and has a distinct subgenus to itself. It 

 is the link in the genus Lethe between those species having no sexual 

 characters on either wing and those having sexual characters on both 

 wings. In Ceylon it is a widely distributed but apparently local insect, 

 and may yet be found in Southern India when that country has been 

 more fully explored. Prioneris sita, Felder, is a wonderful mimic of 

 Delias eucharis^ Drury, though its manner of flight ia quite different. The 

 mimicry cannot be accepted on the usual grounds as it is a fast-flying 

 insect and seemingly well able to take care of itself ; though manifestly 

 it must be an immense advantage to the insect to be mistaken when at 

 rest (when butterflies are most liable to danger from their natural foes) 

 for an inedible species, such as D. eucharis is, and the mimicry is shown 

 by the coloration and markings of the underside only, which is the 

 surface exposed, all Fierinae resting with closed wings. 



A perusal of this paper will show that we have endeavoured 

 indirectly to bring tp notice the very incomplete knowledge we yet 



