Abstract
Two strains, the early-season and late-season ones, of Torymus beneficus, a parasitoid of the chestnut gall wasp, differed from each other in the correlation between the ovipositor sheath length and the lateral length of thorax. The difference in this correlation was much more conspicuous between T. beneficus and T. sinensis, another parasitoid of the pest. In males, there was a wide overlapping in the frequency distribution of the lateral length of the thorax between the two species. In both sexes, no fundamental interspecies difference was detectable through scanning electron microscope examination of the ventral surface of antennal flagella.
