none Trioxys complanatus Quilis (Hymenoptera: Aphidiidae) was introduced into South Australia in August 1977 as a primary parasite of the spotted alfalfa aphid Therioaphis trifolii (Monell) f. maculata . The first hyperparasites of T. trifolii f. maculata were not recorded from field-collected T. complanatus pupae until April 1978, some 8 months after the initial releases of T. complanatus . Four species of aphid hyperparasites have been found attacking T. complanatus , viz. Dendrocerus aphidum (Rondani), Pachyneuron aphidis Bouche, Phaenoglyphis villosa (Hartig) and Myiocnema sp. Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Land and freshwater zones; Australasian region; Australia Trioxys complanatus (Braconidae); Hymenopteran parasites; Dendrocerus; Myiocnema; Pachyneuron & Phaenoglyphis; Hyperparasitism in hemipteran host; Hemipteran hosts; Therioaphis trifolii form. maculata; Hymenopteran hyperparasites; Hyperparasitism; Hymenopteran parasites in Therioaphis (Hemiptera) host; Australia; South Australia; Hymenopteran hyperparasites in hemipteran host Phaenoglyphis (Cynipidae ); Chalcidoidea; Dendrocerus (Megaspilidae ); Hymenopteran hosts; Trioxys complanatus; Hyperparasitism in hemipteran host; South Australia Therioaphis trifolii form. maculata (Aphidoidea); Hymenopteran parasites; Trioxys complanatus; Hymenopteran hyperparasitism; Hyperparasitism; Trioxys complanatus (Hymenoptera) & hymenopteran hyperparasites; South Australia