Detailed biological information is lacking on Chelonus sp. nr. curvimaculatus, an egg-larval parasitoid of Pectinophora gossypiella (Saunders). We conducted laboratory studies to gain new understanding of the biology of C. sp. nr. curvimaculatus reared on this economically important host. Developmental time, adult longevity, and fecundity of C. sp. nr. curvimaculatus were studied under 5 constant temperatures and 3 photoperiods. At 20 degrees C, parasitoid development, from egg to adult, was longer for females (53.6 d) than for males (49.5 d), but at 35 degrees C both sexes developed in a similar period (19.9 d for females and 18.8 d for males). The thermal constant for female and male C. sp. nr. curvimaculatus, from egg to adult, was 366 and 353 above a base temperature of 12.95 degrees C and 12.47 degrees C, respectively. Adult male (approximately 16.5 d) and female (approximately 20 d) parasitoids lived longest at 20 degrees C, and at 35 degrees C both lived approximately 6.5 d. True and realized fecundity was highest at 25 degrees C (approximately 1,034 and 420 eggs per female, respectively) and lowest at 35 degrees C (approximately 119 and 67, respectively). The percentage of superparasitized host eggs was greatest at 25 and 30 degrees C (approximately 55%), and lowest at 35 degrees C (approximately 29%). Net reproductive rates (Ro) were variable across all conditions. Based on the realized fecundity, Ro was highest at 20 degrees C (103.37) and lowest at 35 degrees C (32.79). Temperature and the age of the parasitoid had the greatest influence on fecundity. Photoperiod played a minor role in influencing developmental rates, but not adult longevity or fecundity of C. sp. nr. curvinaculatus. This life history and rearing information should be useful in field release studies and the development of future biological control programs for pink bollworm. none