“…Such a life cycle was observed in the River Samson for Ephemerella major (Rosillon, 1986) and it was thought to be likely for the other 10 species from data on phenology and occurrence of pupal and early stages (Rosillon, 1984(Rosillon, , 1985b and from other studies of their life histories in European temperate rivers (Pleskot, 1961;Thorup, 1963;Elliott, 1968Elliott, ,1982Thibault, 1971;Otto, 1976;Streit, 1976;Dessaix & Roux, 1980;Goedmakers, 198 1).…”