Three new species belonging to two genera of the family Braconidae (Hymenoptera) are recorded from a dipterous aquatic leaf miner on Lagarosiphon major (Hydrocharitaceae): Ademon lagarosiphonae sp. n. (Opiinae) and Chaenusa anervata sp. n. and C. seminervata sp. n. (Alysiinae: Dacnusini). The genera Ademon Haliday, 1833, and Chaenusa Haliday, 1839, are new for the fauna of South Africa.