Females of ormiine tachinids fly to their hosts' calling songs and deposit larvae on the host or nearby. Two species, Ormia ochracea (Bigo0 and O. depleta (Wiedemann), were reared for at least 8 generations, making them the first ormiines to be laboratory-propagated. Both were reared on natural hosts : Gryllus spp. field crickets (principally G. rubens) for O. ochracea, and Scapteriscus spp. mole crickets for O. depleta. Commercially reared Acheta domesticus tested as hosts were less satisfactory. Hosts were parasitized manually or by confinement with flies or planidia (infective larvae). Transparent, cylindrical, sleeved cages were designed to accommodate parasitized hosts and pupae and adults of O. ochracea. Cages were joined to allow O. ochracea to cycle through its stages with minimum handling and care. Parasitized hosts and pupae of O. depleta were held in containers of damp sand ; adults were held in cages developed for O. ochracea.Adults of both species were maintained on applesauce, sugar cubes, powdered milk, and water. The life cycle of O. ochracea was about 31 days and of O. depleta about 36 days, with the principal difference being the time required for planidia to complete development. In O. ochracea the adults emerged synchronously but in O. depleta males preceded females. In both species sex ratio was generally 1 : 1 and females lived slightly longer than males. O. depleta from our laboratory colony have been released for biological control of mole crickets.