Abstract: Three days old female of Microplitis mediator (Haliday) parasitized 5 days old 2.7, 5.6, 8.7, 9.0 larvae of Agrotis segetum and 1.8, 4.0, 7.7, 9.2 A. lipsilon larvae in 1, 3, 6 and 12 hours duration respectively. The parasitic female of the same age parasitized 7.1, 8.7, 2.9, 1.4 Agrotis segetum and 6.7, 7.6, 3.2, 1.1 A. ipsilon larvae of 3, 5, 7, and 10 days old in 6 hours duration respectively. The female parasitized 2.9, 8.7, 8.0, 7.7 A. segetum and 4.4., 7.6, 8.8, 10.0 A. ipsilon out of 5, 10, 15 and 20 number of each host larvae in 6 hours duration respectively. The female parasitized 37.8, 34.6, 33.6 A. segetum and 29.2, 26.6, 25.4 A. ipsilon larvae till her death at 20±2°C, 25±2°C and 30±2°C and 60 - 70 percent r.h. and 14 hours light respectively.