NOTES ON NEW GUINEAN SPECIES OF TRIPTEROIDES, SUBGENUS RACHISOURA (DIPTERA, CULICIDAE), WITH DESCRIPTIONS OF TWO NEW SPECIES BY J. VAN DEN ASSEM Public Health Department, Malaria Control Service, Netherlands New Guinea Introduction The genus Tripieroides occurs in the Oriental and the Australasian regions. After Edwards (1932) the genus is divided into 4 subgenera: Äiaor/goeld/a (monotypic and endemic in New Zealand); Rachisoura (New Guinea and adjacent islands to the east, including the Solomons and N. Australia, with an optimum of at least 20 known species in New Guinea) ; Tripteroides (Oriental and Australasian; an optimum of at least 30 species in the Philippines) and Mime-teomyia (Australasian). Belkin (1950) gives a detailed account of the geographical distribution of the subgenera. Revision of subgeneric characters seems necessary, however, in the light of recent discoveries (Belkin, 1950; Baisas & Ubaldo-Pagayon, 1952). The subgenus Rachisoura, as understood in the present paper, is a natural, rather well defined taxon; the adults are unornamented and characterized by a pattern of broad wing scales at least on veins 1 and 2; in the larvae there are highly modified maxillae whereas thoracic spines are absent. The distribution of the subgenus is rather limited and within this area many species seem to have a limited distribution of their own: known species from New Guinea at least 20 (continued collecting certainly will add to this number), from the Solomons 3; from tropical Australia 2. All Solomon species are endemic and so are most of New Guinea. Only two species occur in both New Guinea and Australia (T. jili-pes and T. hrevirhynchus). Baisas & Ubaldo-Pagayon (I.e.) described a Philippine species, T. j?iabmi, which they included because of the larval maxillae in the subgenus Rachisoura; this species, however, is extremely aberrant from all other Rachisoura species. As modified larval maxillae also occur in still another subgenus {Mimeteomyia') (Belkin, 1950) and also because of its geographic relations it is much more acceptable to understand mahini as an offshoot of the subgenus Tripteroides, resembling a Rachisoura by a convergent development of the modified larval maxillae, rather than widening the definition of the subgenus Rachisoura to a meaningless conception. Larvae of many Rachisoura species (in fact many species of the other sub-genera as well) live in a quite peculiar habitat, viz, in the liquid inside the pit-chers of Nepenthes, an environment which requires special adaptations to be 35
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