"Brine flies" of the genus Ephydra are often very abundant in coastal salt marshes, lagoons and rock pools; salt and alkaline lakes, ponds, and salinas; salterns where salt is evaporated for human use; and around thermal and mineral springs. The 13 recognized Old World species are redescribed and figured, and a key is presented for identification based mainly on characters of the male genitalia. The Old World species all belong in the subgenus Ephydra, s. str., and are classified in three groups, the bivittata, glauca, and riparia groups. Three new species are described in the riparia group: stuckenbergi from South Africa and Madagascar, magadiensis from Kenya, and murina from Iraq and the area westward to Bulgaria. From a study of types an attempt is made for the correct application of names from the earlier literature, and corrected synonymies include strenzkei Soika new syn. of riparia Fallén. Ephydra alandica Frey is considered to be a Baltic subspecies of macellaria Egger (new status).