The Author describesPsychoda sanfilippoisp. n., a brachypterous species of Mount Kenia which inhabits the leaf frills found at the base of senecios.Ps. sanfilippoiresults to be the third brachypterous species of the Psychodidae family. The Author emphasizes the importance of wing modifications in relation to brachyptery and forwards an hypothesis for the probable causes which lead to the origin of this species.