"The list here given is chiefly taken from the catalogue published by Dr. Hagen, and containing descriptions of the species named by him or by M. Nietner. They were found in the most elevated parts of the island, near Rambodde, and Dr. Hagen informs me that not less than 500 species have been noticed in Ceylon, but that they are not yet recorded, with the exception of the species here enumerated. It has been remarked that the _Trichoptera_ and other aquatic _Neuroptera_ are less local than the land species, owing to the more equable temperature of the habitation of their larvæ, and on account of their being often conveyed along the whole length of rivers. The species of _Psocus_ in the list are far more numerous than those yet observed in any other country, with the exception of Europe. Order HYMENOPTERA. "In this order the _Formicidoe_ and the _Poneridoe_ are very numerous, as they are in other damp and woody tropical countries. Seventy species of ants have been observed, but as yet few of them have been named. The various other families of aculeate _Hymenoptera_ are doubtless more abundant than the species recorded indicate, and it may be safely reckoned that the parasitic _Hymenoptera_ in Ceylon far exceed one thousand species in number, though they are yet only known by means of about two dozen kinds collected at Kandy by Mr. Thwaites. Order LEPIDOPTERA. "The fauna of Ceylon is much better known in this order than in any other of the insect tribes, but as yet the _Lepidoptera_ alone in their class afford materials for a comparison of the productions of Ceylon with those of Hindostan and of Australasia; 932 species have been collected by Dr. Templeton and by Mr. Layard in the central, western, and northern parts of the island. All the families, from the _Papilionidoe_ to the _Tineidoe_, abound, and numerous species and several genera appear, as yet, to be peculiar to the island. As Ceylon is situate at the entrance to the eastern regions, the list in this volume will suitably precede the descriptive catalogues of the heterocerous _Lepidoptera_ of Hindostan, Java, Borneo, and of other parts of Australasia, which are being prepared for publication. In some of the heterocerous families several species are common to Ceylon and to Australasia, and in various cases the faunas of Ceylon and of Australasia seem to be more similar than those of Ceylon and of Hindostan. The long intercourse between those two regions may have been the means of conveying some species from one to the other. Among the _Pyralites, Hymenia recurvalis_ inhabits also the West Indies, South America, West Africa, Hindostan, China, Australasia, Australia, and New Zealand; and its food-plant is probably some vegetable which is cultivated in all those regions; so also _Desmia afflictalis_ is found in Sierra Leone, Ceylon, and China. Order DIPTERA.