I was three months in the island of Batchian before I obtained a specimen of this fine insect, which I had seen once or twice only flying high in the air. I at length came upon it flying about a beautiful cinchonaceous shrub with white bracts and yellow flowers (_Mussænda_, sp.); and having cleared a path round about, I visited the place every morning on my way to the forest, and once or twice a week had the satisfaction of capturing a fine male specimen of _O. Crœsus_. The females were more plentiful and more easily caught. I afterwards sent out one of my men with a net every day to look after this insect only. He would stay out all day long, wandering up a broad rocky torrent, where the males flew up and down occasionally or settled on the rocks which just appeared above the water. He generally brought me one, and sometimes even two or three specimens; and thus, with those that I myself captured at the flowers, I secured a fine series of this richly coloured species. 4. ORNITHOPTERA TITHONUS, De Haan. _O. Tithonus_, De Haan, Verh. Nat. Gesch. Ned. t. 1. f. 1. _Hab._ S.W. Coast of New Guinea (_Leyden Museum_). This remarkable species must be very rare, as I never saw it in any part of the New Guinea district that I visited; nor was it seen during the exploration, a few years ago, by a Dutch steamer which visited the part of the coast where the only specimen known was said to have been obtained. 5. ORNITHOPTERA URVILLIANA, Guérin. _Papilio Urvilliana_, Guér. Voy. de la Coquille, Lép. t. 13. f. 1, 2, ♂. _O. Urvilliana_, Boisd. Sp. Gén. Lép. p. 175. _Hab._ New Ireland (_Paris Museum_). b. _Pompeus_ group. 6. ORNITHOPTERA REMUS, Cramer. _Papilio Remus_, Cr. Pap. Ex. t. 135. f. A, t. 136. f. A (♀), t. 386. f. A, B (♂); Fab. Syst. Ent. iii. 1. p. 11. _O. Remus_, Bd. Sp. Gén. Lép. p. 176. _Papilio Panthous_ ♂, Clerck, Icon. t. 18 (♀). _Hab._ Amboyna, Ceram, Gilolo, Morty Island, Sulla Island, Celebes (_Wall._).