First record of Mythicomyia Coquillett, 1983 from Colombia with description of a new species of Mythicomyia (Heterhybos) Brthes, 1919 (Diptera: Mythicomyiidae: Mythicomyiinae) and an updated key to South American species.

Mythicomyia Coquillett (1893) has a disjunct distribution (presence in every biogeographical region with the exception of the Palearctic) and is a poorly studied group in the Neotropical Region, and completely unknown in Colombia. Its subgenus Heterhybos Brthes has a Nearctic and Neotropical distribution. Of the nine species in the Neotropical Region (in Argentina, Chile, and Uruguay), all occur in Chile and only one in Argentina and Uruguay. A new species of Mythicomyia (Heterhybos) is here described from Colombia: Mythicomyia (Heterhybos) bilobata sp. nov. (type-locality: Liborina, La Sucia). Illustrations of the new species, dichotomous key (males and females) and distribution map of the South American species are also presented.