Natural host.—Platyzosteria sp., Tasmania (Riek, 1955).
Riekella sp.
Synonymy.—Nephrites sp. [Selander, 1957].
Natural host.—Platyzosteria castanea, Australia Capital Territory (Riek, 1955).
Biology of Australian Ripidiini.—The Australian species of Ripidiini are parasites of apparently endemic, ground-dwelling species of cockroaches. There is some correlation between host subfamily and parasite genus: Riekella spp. [= Nephrites] have only been bred from Blattinae. Rhipidioides spp. occur only in the closely related Ectobiinae and Pseudomopinae. Neonephrites and Neorhipidius also occur in the Pseudomopinae. Paranephrites occurs in the Panchlorinae. There is some evidence that the parasitized cockroaches migrate onto trees when the larval parasite is mature, as pupae have only been found on the trunks of eucalyptus trees. In all species the larva leaves the host dorsally through an intersegmental membrane. The host continues to live for a few days after the parasite emerges. The larva attaches itself to bark on the tree trunk by a few strands of silk before pupating. The larviform, wingless female remains near the pupal skin and is sought out by the winged male. The eggs are laid in a mass around the pupal skin (Riek, 1955).
Ripidius[5] boissyi Abeille
Balduf (1935) lists Ripidius boissyi as parasitic on nymphs of Ectobius pallidus giving Abeille de Perrin (1909) as a source for this information. However, Abeille de Perrin simply presumed that R. boissyi parasitized E. pallidus because he collected this cockroach in the same habitat as the beetle. Abeille de Perrin suggested that the species of the genus Ripidius lived in the bodies of cockroaches, but there are no rearing records, as far as we know, of R. boissyi from cockroach hosts.
Ripidius denisi Chobaut
Chobaut (1919), in France, collected both R. denisi and Ectobius pallidus when beating an oak tree. Because of the known association of other species of Ripidius with cockroaches, he presumed that this beetle was parasitic on E. pallidus, a cockroach common in this beetle's habitat.