Development and survival of melon fly, Bactrocera cucurbitae (Coquillett), oriental fruit fly, B. dorsalis (Hendel), B. latifrons (Hendel), and Mediterranean fruit fly, Ceratitis capitata (Wiedemann) eggs, larvae, and pupae were compared at 5 constant temperatures ranging from 16 to°C. Durations of the immature stages of B. cucurbitae, C. capitata, B. dorsalis, and B. latifrons ranged from 12.9 to 40, 14.7 to 46.2, 15.4 to 47.1, and 18.2 to 61.6 d, respectively, at 32–16°C. Species differed most conspicuously in duration of the egg stage and least conspicuously in duration of the pupal stage. Survivorship data indicated that B. latifrons was adapted to a narrower range of temperatures than the other 3 fruit fly species. Developmental thresholds were lower for the larval stage than for the egg and pupal stages for all species. Threshold values for all stages of C. capitata were lower than those for all Bactrocera species. Thermal requirements (degree-days) for development in the pupal stage were greater than those of the egg and larval stages in all species, and the requirements of B. latifrons were greater than those of the other species within each stage. These findings are discussed with respect to commodities treatment research, rearing, control methods using mass-reared insects, and fruit fly temporal and geographical patterns.