none. Immature forms of Diadegma trichoptilus (Cameron), a larval parasitoid of Exelastis atomosa Wals. were studied under laboratory conditions (24 +- 1 degree C, 55-60% R. H.). The ovarian eggs were elongately curved. Newly deposited eggs averaged 0.210 mm in length and 0.055 mm in width. All five larval instars were legless. The first and IInd instars were caudate type and the remaining 3 instars hymenopteriform. The length and width of five instars averaged 1.20 and 0.158, 1.88 and 0.253, 3.00 and 0.754, 4,736 and 1.070 mm. respectively. The mean length and width of mandibles in five instar averaged 0.019 and 0.013, 0.028 and 0.019, 0.037 and 0.025, 0.066 and 0.033, 0.88 and 0.56 mm. respectively. Pupae averaged 5.00 mm. in length. There exists a significant correlation between larval age and larval body form (L : P lt 0.05; W : P lt 0.05).