Two new species of Lanthanusa ris, from the high mountains of new Guinea (Odonata)

Up to the present, three species of the Libellulid genus Lanthanusa Ris have been described, all from the mountain regions of New Guinea. One of these, the genotype L. cyclopica Ris, is a female in the Leiden Museum collected more than half a century ago somewhere in the Cycloop Mountains (North New Guinea) ; the male has remained unknown and the species has never been found again. Two others, richardi Lieft, and lamberti Lieft., were subsequently discovered in the mountain forests of central New Guinea and are known from both sexes. All three species have been discussed at length in the writer's account of the Anisoptera of the Third Archbold Expedition (Treubia, 1942, 18 : 493-499, figs. 40-45). In this short paper the descriptions are offered of two more species, one from the high mountains of northeast New Guinea, and one from the island Goodenough. It is interesting to see that all members of Lanthanusa are apparently restricted to high elevations and do not occur below a height of about 1350 metres above sea-level, L. lamberti from the moss-forests near Lake Habbema (2800-2850 m) being the highest recorded Libellulid from New Guinea. Owing to their cryptic colouring the adults are probably easily overlooked insects as they rest on leaves in sunlit openings of the forest. The larva is still unknown but, like Huonia, the insects probably breed in forest-marshes or small streams. Lanthanusa sufficiens, sp. n. (figs. 1-4) Material. — 3 ♂, 3 ♀ (2 ♀ juv.), Eastern extremity of New Guinea: d'Entrecasteaux Is., Goodenough I., east slopes, 1600 m, 11-12.X.1953, K. M. Wynn & L. J. Brass. Holotype ♂ and allotype ♀ in the Leiden Museum,