Within five species of parasitoid wasps of the families Pteromalidae (Morodora armataGahan,Muscidifurax zaraptorK.&L.,Nasonia vitripennis(Walker)), Bethylidae (Goniozus legneriGordh), and Tiphiidae (Myzinum quinquecinctum(Fabricius)), we found significant positive correlations between female body size and both the number and the size of the mature oocytes present in the ovaries. These data are discussed with reference to current clutch size and egg size models and biological information available on these species.