A revision of the genus Rondani (Diptera, Diopsidae) in Sri Lanka with descriptions of two new species and a review of the other stalk-eyed flies from the island.

The literature on Sri Lankan Diopsidae is reviewed. Eight Diopsidae are now known to occur in Sri Lanka, five species in the genus and one species each in the genera , , and . The presence of requires confirmation to exclude the possibility of mislabelling. All five species are endemic, as are the species and probably the species. Only Senior-White has a larger distribution as it also occurs in India. A key is presented for the Diopsidae of Sri Lanka. Three species were already known to occur in Sri Lanka: Röder, Feijen and Feijen. These species form the species group. Two new species are now described for this group: and is redescribed, as an earlier redescription turned out to be based on a series of specimens of its sister species The other three Diopsidae of Sri Lanka are listed and illustrated. Allometric aspects of the five species are discussed. Three species are sexually dimorphic with regard to eye span, while two species are monomorphic. It is assumed that sexual dimorphism developed independently in the species group. This brings the number of known cases of independent development of sexual dimorphism in the Diopsidae to ten.