Up to this day only a single information concerning the Lepidopterous fauna of the island of Billiton, situated between Sumatra and Borneo, was published (see: Godman, Salvin and Druce in Proceed. Zool. Soc. of London for 1878, p. 637, pl. 40). This communication was based upon a small collection made by Mr. S. N. Walter and consisting of thirty-three species. A more extensive collection, however, was received in 1888 by Mr. M. C. Piepers, which collection owed its origin to the following circumstances: During the month of June 1888 Mr. A. G. Vorderman, town-surgeon at Batavia, undertook an excursion to Billiton and the neighbouring island of Mendanao for the sake of his Ornithological studies. In the meantime he had brought together, besides many other natural history objects, an important collection of Lepidoptera, chiefly Rhopalocera, which, for the greatest part, was sent by him to Mr. Piepers. In none of these islands high mountains are found, and the height of the localities where the insects were captured does not surpass 3000 feet. The Lepidoptera, which at present make part of our collection, are of great interest, especially with regard to their geographical connection with those of the neighbouring islands of Sumatra and Borneo, and of the peninsula of Malacca. In my original paper (see Tijdschr. v. Entom. XXXIII, p. 279; pl. 12) all the differences I met with are carefully mentioned, in order to increase the value of my remarks, and to make use as much as possible of the important collection brought together by Mr. Vorderman.