Life table studies were conducted in the laboratory for the eulophid gregarious pupal parasitoid, Tetrastichus sp., on Hyphantria cunea Drury at a constant temperature of 28.2$pm$2$^{circ}C$, 50-60% RH to evaluate their impact on the host and their potential biological control. Development of immature stage took 20.1$pm$2.7 d: adult females lived for 23.2$pm$2.2 (range, 16-27)d and produced a mean of 53.6$pm$26.6 adult progeny per female, with a sex ratio of 1: 9.5 (M:F). The intrinsic rate of natural increase (r$_{m}$) was 0.178/ female/day; the net reproductive rate (R$_{o}$), 46.74; the capacity for increase (r$_{c}$) 0.177; the finite rate of increase (λ) 1.19/female/day; thus each female contributed 46.74 individuals to the population in a mean generation time of 21.6 d. Biological factors in determining the life history trait variation of the parasitoid were discussed.d.d.d.