I. Introduction The present paper has been written for practical purposes in the first place. It intends to provide medical men in the field with some useful information on important mosquitoes. It is also meant to rouse some interest in those insects, that are of primary importance to public health. Three main categories will be dealt with : (a) Species known to be vectors of any human disease in the New Guinea territory; (b) Man-biting species without vector properties, merely annoying by their numbers (pest-mosquitoes) ; (c) Some species, not man-biting, but easily recognizable, wide-spread, and frequently present in mosquito collections. The present synopsis has no pretentions as to its complete originality. Bonne-Wepster & Brug (1937, 1939) already published a paper on 40 Culicines, later on modernized and extended to one hundred species by Bonne-Wepster (1954). Both these reviews, however, which are more or less out of date by now, are dealing with the whole area of the former Dutch East Indies, i.e. the Indonesian Republic including Western New Guinea This area includes parts of two entirely different faunistic provinces (the oriental and the australian), between which a natural, be it somewhat flexible, borderline exists. From a New Guinea point of view both papers carry a lot of ballast species : orientals, not occurring in the territory. On the other hand some New Guinea species which have become known as common are scarcely mentioned, or omitted. The monograph by Bonne-Wepster & Swellengrebel (1953) on the anophelines of the Indo-Australian region is hardly accessible to a non-entomologist because of the huge number of species dealt with. Yet, the anopheline fauna of New Guinea proper is poor