The development, reproduction, and life history of Encarsia citrina Craw were studied in the laboratory on San Jose scale, Quadraspidiotus perniciosus (Comstock), at constant temperatures of 15, 17.5, 20, 25, 27.5, and 30°C at 60–70% RH, and a photoperiod of 16:8 (L:D) h. Larval development did not occur at 15 and 30°C. Total developmental time varied from 22.7 d at 27.5°C to 47.4 d at 17.5°C. The lower development thresholds for larval, pupal, and egg to adult periods were 10.4, 6.3, and 9.0°C, respectively. The number of degree-days required to complete development was 434.8. The average longevity of adults ranged from 34.3 d at 15°C to 8.0 d at 30°C. The average fecundity of females ranged from 96.3 eggs at 20°C to 40 eggs at 17.5°C. Life table parameters were also determined at four constant temperatures (17.5–27.5°C). The intrinsic rate of increase, r_m, values for E. citrina ranged from 0.074 at 17.5°C to 0.176 at 27.5°C. The highest net reproductive rate, R₀, of 93.7 female offspring/female was estimated at 20°C. The mean generation time, T, ranged from 49.3 d at 17.5°C to 23.4 d at 27.5°C. The results of this study emphasize E. citrina survival and population growth under varied temperature conditions.