1895.] L. de Niceville & Dr. L. Martin— Butterflies of Sumatra. 493 



outer black margin, this form being the G. chryseis of Drury. It is 

 quite typieal throughout the Malay Peninsula, but when it reaches the 

 latitude of Burma it gradually merges into typical G. pyranthe, which 

 latter is found all over India and Ceylon. It is not seasonally dimor- 

 phic in Sumatra as it is in India. In our area it is found only at low 

 elevations, not higher than Namoe Oekor, where it is local owing to 

 the presence or absence of Cassia alata, Linnaeus, the food-plant of 

 its larva. As this tree is very partial to swampy ground, and even 

 grows in swamps with brackish water, C. pyranthe occurs very near 

 the sea, and flies all the year round. It has only one form of female, 

 but it is variable, some specimens being much more melanic than 

 others. The larva is quite green, without the lateral brown streak of 

 C. crocale, Cramer. The pupa has a blunt rounded head, not a pointed 

 one as in G. crocale. 



535. Catopsilia scylla, Linnseus. 



Snellen. Grose Smith. Hagen. Kirby. Distant. "Wallace. 

 Dr. B. Hagen informed Dr. Martin that this species was not at all rare 

 near Medan, the capital of the Deli district, from 1879 to 1882. 

 Dr. Martin had never seen it in the plains, and had received a few 

 specimens only from the Central Plateau from Battak collectors. In 

 Penang and Singapore on the mainland of Asia it is always very com- 

 mon in gardens. So Dr. Martin would hardly believe Dr. Hagen 

 that G. scylla belonged to the fauna of the plains of Sumatra, especially 

 as Dr. Martin never saw or obtained any specimens from 1882 to 

 1894. Suddenly in August and September of the latter year, after 

 nearly twelve years interval, G. scylla appeared everywhere in Deli 

 and Langkat in suitable places such as gardens and fallow-land near 

 houses where Cassia sophera, Linnaeus, the food-plant of the larva, 

 grows. Since then C. scylla belongs to our fauna, although it is the 

 rarest of all our Catopsilias, and we would call attention to the in- 

 teresting fact that a butterfly has disappeared for twelve years from 

 a spot in every way apparently suitable for its existence, and has again 

 reinstated itself by immigration from the south-west (the Battak and 

 Gayoe mountains) or from the east (the Malay Peninsula over the 

 shallow Straits of Malacca). The larva is dark velvety -green, with 

 a yellowish-white lateral streak, and some very minute black spots 

 on each segment anterior to the streak, the whole surface delicately 

 ringed or indented like a leech. The pupa has a pointed head like 

 that of C. crocale, Cramer, but is shorter and more convex than the 

 slender pupa of that species. 



