none Host acceptance for parasitization by Alysia manducator is divided into four stages: contact with the fly larva (usually antennal), probing by the ovipositor, attack (an attempt to stick the ovipositor) and oviposition. Rejection of the host is possible on every stay. Passage from the contact to the probing is stimulated by the smell of carrion and by movements of the larvae. The probability of passage to the probing increases with increasing of the dimension of the larvae, but does not depend on the host species of all studied carrion-feeding Diptera. The probability of passage from the probing to the attack, on the contrary, is host-specific but does not depend on the dimension of the larvae. The probability of passage to the oviposition is also host-specific. Some of the eggs of the parasitoid died in all hosts. Probability of successful completion of larval development depends on the ability of the parasitoid to control host's ontogeny. This ability is realized in the limited range of blowflies. Probability of successful emergence of adult parasitoid from puparium depends on host species too. Reliable positive correlation between host acceptance and suitability testifies to adaptiveness of parasitoid's behavior, in spite of "mistaken" ovipositions, which sometimes happen.