Abstract In assays at constant temperatures, Spalangia gemina Boucek, Spalangia cameroni Perkins, and Muscidifurax raptor Girault and Sanders females killed more house fly ( Musca domestica L.) pupae at 30°C than at 15, 20, 25, or 35°C, with attack rates for the three species of 11.2, 12.6, and 21.1 pupae killed per parasitoid per day, respectively. Progeny production followed a similar pattern, with maximum rates of 6.8, 7.5, and 9.2 progeny per day at 30°C for S. gemina, S. cameroni, and M. raptor, respectively. Both Spalangia species produced proportionally fewer males at higher temperatures than at lower temperatures; sex allocation by M. raptor was relatively unaffected by temperature except for a trend to produce fewer females at 15°C (29.6% females) than at higher temperatures (43–47%). The four-parameter thermodynamic model of Sharpe and DeMichele with high temperature inhibition fit the attack rate and progeny production rate data well. These models were very effective at predicting host attacks and parasitism at high, variable temperatures typical of outdoor mid summer conditions in many regions, provided that 1-h time steps were used in rate summation algorithms. Assays for long-term net rates of fly destruction revealed that S. gemina and S. cameroni would be most effective for fly control at 25°C and substantially less effective at either low (15°C) or high (35°C) temperatures. M. raptor was equally effective at killing house fly pupae over the 15–30°C range, but was significantly less effective at 35°C.