none Enter Adults of the woodwasp Tremex longicollis Konow (Hymenoptera: Siricidae) oviposit in the wood of dying Celtis sinensis trees using their ovipositors, and adults of the parasitoid Megarhyssa jezoensis (Matsumura) (Hymenoptera: Ichneumonidae) deposit eggs into the woodwasp larvae that live in the wood, also using their long ovipositors. Many T longicollis ovipositors, both with and without abdominal segments, and a M. jezoensis ovipositor were found stuck in C sinensis wood at two parks in Osaka Prefecture, central Japan. Field observations showed that ovipositing woodwasps and parasitoids were attacked by predators during the daytime, and their ovipositors were left behind in the wood. Woodwasps and their parasitoids, which have long ovipositors, may be vulnerable to predation during oviposition. (C) Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society, 2009 Published by Elsevier B.V. All rights reserved. BR Reproduction. Reproductive behaviour. Parasites diseases and disorders. Parasites. Insect parasites. Hosts. Insect hosts. Ecology. Land zones. Palaearctic region. Eurasia. Asia. Megarhyssa jezoensis (Ichneumonidae): Parasite, Prey; Tremex longicollis (Siricidae): Host, Prey. Megarhyssa jezoensis: Egg laying, Oviposition, Hymenopteran hosts, Tremex longicollis, Predators, Possible predators identification, Japan, Honshu, Osaka; Tremex longicollis: Egg laying, Oviposition, Hymenopteran parasites, Megarhyssa jezoensis, Predators, Possible predators identification, Japan, Honshu, Osaka. ST Animalia, Arthropoda, Insecta, Hymenoptera, Apocrita, Terebrantia, Ichneumonoidea, Ichneumonidae; Animalia, Arthropoda, Insecta, Hymenoptera, Symphyta, Siricoidea, Siricidae. Arthropods; Hymenopterans; Insects; Invertebrates.