The effect of constant temperatures on developmental time and parasitization rate of Citrostichus phyllocnistoides was evaluated on Phyllocnistis citrella at nine constant temperatures ranging from 15ºC±1 to 35ºC±1 in 2.5ºC increments in the laboratory. Developmental periods of immature stages ranged from 34.98 days at 15ºC to 9.15 days at 35ºC. The lower developmental threshold for C. phyllocnistoides estimated was 8.93°C. Mortality rate of immature stages decreased as the temperature increased, ranged from 27% at 15ºC to 8% at 35°C. Longevity of both sexes were different at all temperatures studied (except 30 and 32.5°C), ranged from 22.1 days at 15°C to 8.0 days at 35°C for males and 23.8 days at 15°C to 8.3 days at 35°C for females. Parasitization rate of C. phyllocnistoides on Phyllocnistis citrella increased with the temperature up to 32.5ºC being 49%, then decreased at 35ºC.