The average incubation period of eggs of the parasitoid Micro-pikes rufiventris was about 1.23 days,the first larval instar 3.02, the second 2.47 and the third instar 1.28 days, whereas the prepupal and pupal stages lasted on the average about 0.43 and 6.89 days, respec­tively. During the first 48 hours after parasitism, slight differences oc­curred in the body length, body weight and the amount of food eaten by the healthy and parasitized 5.1ittoralis larvae. This could be attributed to the fact that the parasitoid was still in the egg stage and both the para­sitized and unparasitized larvae consumed approximately the same quan­tity of castor bean leaves. From the 3rd to 7th days of parasitism, the body length, body weight and the amount of food eaten by parasitized larvae gradually increased till the emergence of the parasite, but not with the same degree as compared to unparasitized larvae.However, the parasitized larvae ceased feeding on the eighth day after the larvae of parasite became full grown till the host died. The ratio of the amount of food eaten by the parasitized and unparasitized larvae was 1: 3.16. Adults of parasitoid were fed on 1555sucrose solution contami­nated with 10, 15, 20, 25,30 and35 ppm of baythroid for 24 hours. The LC50 values were 19.0 ppm for males and21.0 ppm for females. When males and females were fed on 15% sucrose solution con­taminated with 4, 8, 12, 16, 20 and24 x 10⁴ S.U. of a delfin negative relationship was observed between their longevities and the concentra­tions of the bioinsecticides. Mates and females fed on the contaminated solution of 4, 8, 12, 16, 20, and 24 x 10⁴ S.U. of delfin each combined with 9.2 ppm (LC10 level of baythroid) the longevities gradually decreased by increasing the concentrations of insecticides. Generally, there were positive relationships between the present mortality of the treated adults of parasitoid and the different concentra­tions of delfin, baythroid and combinations of both of them. Also, fe­males were more tolerant than males of the same age and at the same concentrations.Baythroid caused more damage for males and females of the parasitoid than delfin or a mixture or both of them.