none The effect of constant temperatures: 30, 25 and 20 +- 1 degree C combined with photoperiods of 0L:24D, 6L:18D, 12L:12D, 18L:6D and 24L:0D on the production of the solitary larval parasite Microplitis rufiventris Kok, using the non-diapausing host larvae of Spodoptera littoralis (Boisd.) was experimentally studied. The refine development of the parasite, i.e., the highest yield of parasite cocoons through the first 2 days of the emergence period from the parasitized host larvae is achieved under long photoperiod (18L:6D) and (24L:0D) at 30 degree C; short photoperiod (6L:18D) at 25 degree C; and complete darkness (0L:24D) and short photoperiod (6L:18D) at 25 degree C. At 20 degree C the photoperiod has a considerable effect on the developmental speeds of the egg-larval and pupal stage of the parasite.