Rates of parasitization of the pea weevil,Bruchus pisorumL., byEupteromulus leguminisGahan were studied on nine genotypes of peas,Pisum sativumL. There were significant differences in percentages of weevils parasitized among the different pea genotypes. A small, though highly significant, negative correlation between susceptibility to weevil infestation and percentage of parasitized weevils was found. Adult parasites emerged from pea seeds through exit holes made by pea weevil larvae. Those parasites that killed weevil larvae before completion of the exit hole (4.9%) were trapped within the seed.