The genus Colonomyia Colless contains six species in the Australasian and Neotropical Regions. Several recognized synapomorphies leave no doubt that Colonomyia is a monophyletic group, with the Australasian species more closely related to one another than to the Neotropical species. On arguments derived from the wing venation, Colonomyia is hypothesized to be the sister-group of the genus Ohakunea Edwards, both together representing a lineage distinct from the family-level taxa currently recognized in the Sciaroidea. Colonomyia borea sp. n. from Costa Rica and C. rakelae sp. n. from Papua New Guinea are described. Recognition of these new species extends the distribution of the genus Colonomyia into the tropical zone and the northern hemisphere.