抄録
It is known that the adult emergence curve of Torymus (Syntomaspis) beneficus, a native parasitoid of the chestnut gall wasp, Dryocosmus kuriphilus, has two peaks in the Ibaraki district. Samples of withered galls of D. kuriphilus were collected from various localities and placed in a meteorological screen in Fukuoka to investigate the seasonal prevalence of adult emergence of T. (S.) beneficus. It was evident that there were at least three ecotypes of the parasitoid with defferent curves of adult appearance. As these type sere complicated in their geographical distributions, they should not be regarded as geographical ecotypes which have adapted to the climatic conditions in each locality. Alternatively, it was supposed that these types may have originated from diffrerent ecotypes of the same species which attacked different native cynipid hosts before D. kuriphilus was accidentally introduced into Japan.
