ABSTRACTThree species ofSmittium(Trichomycetes, Harpellales) that may be endemic to Western Australia are described from the hindguts of midge larvae (Diptera, Chironomidae):S. fruticosum, S. angustumandS. microsporum.Axenic cultures were obtained of the latter two fungal species. The occurrence in Western Australia of six geographically widespread species of other Harpellales from dipteran guts is reported together with records ofParamoebidiumspp. (Amoebidiales) in Chironomidae and Ephemeroptera.