none The population of supernumerary parasite progeny of M. rufiventris Kok. inside Spodoptera littoralisa (Boisd.) larvae was studied under different ratios of parasite-host density. At a contant population of host larvae and various levels of parasite density, the regression coefficient revealed that an increase of 0.78% in parasite eggs was found for an increase of every unit population of M. rufiventris. An inverse density-dependent action of the latter was obtained under various densities of S. littoralis larvae at constant populations of the parasite. The regression coefficient indicates that for a unit increase in host density a 0.06% fall in the number of parasite eggs/host larvae was achieved. A fraction of supernumerary parasite progeny was eliminated during the egg-stage. Elimination magnitude of the latter increased with the increase of supernumerary parasite population and vice versa.