On exotic Diptera

The Leyden Museum has from time to time been enriched with small collections of exotic Diptera, which have neither been arranged nor determinated. In looking over these objects, I observed a great many very interesting species among them, and a more accurate examination told me, that a considerable number of them are unknown to science. In the present notes I intend to give descriptions of these new species, together with some observations on other species already described. This first part will treat of the Diptera belonging to the old tribe Nemocera.