none The bionomics of Campoletis chlorideae and the regularity of its seasonal fluctuations were studied in Changsha district, Hunan province. Field investigation indicated that there were ten generations of C. chlorideae a year, of which seven occurred in cotton fields. Three peaks of cotton bollworm parasitization by C . chlorideae were observed, early May to late June, mid August to early September, mid September to mid October respectively. One peak occurred in tomato and tobacco fields, the other two in cotton fields. The parasitization rate ranged from 25.1% - 63.1 % . The total development time from egg to adult ranged from 13.0 days at 32[degree]C to 75.5 days at 11.6[degree]C. Each wasp could parasitize the 5 - 23 second instar larvae of tobacco caterpillar. C. chlorideae could parasitize the cotton bollworm, beet annyworm and tobacco caterpillar, but preferred the cotton bollworm larvae. C . chlorideae could parasitized 1st-3rd instar larvae of the tobacco caterpillar, but seldom parasitzed 4th-6th instar larvae. Moreover, C. chlorideae preferred second instar larvae. Theoretical models for developmental speed, adult longevity and the influence of temperature were proposed. The overwintering of C. chlorideae Uchida was also discussed. Moreover, methods for utilization of C. chlorideae Uchida in crop protection were presented and the bionomics of Campoletis chlorideae in both the Yangtze River Valley and Yellow River Valley were compared. Life cycle and development; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Land and freshwater zones; Palaearctic region; China Helicoverpa armigera (Noctuidae); Hymenopteran parasites; Campoletis chlorideae; Parasitoid bionomics & seasonal prevalence; Hunan; Changsha district; Hymenopteran parasitoid bionomics & seasonal prevalence Campoletis chlorideae (Ichneumonidae); Life cycle; Bionomics; Lepidopteran hosts; Helicoverpa armigera; Parasitoid bionomics & seasonal prevalence; Hunan; Changsha district; Bionomics & seasonal prevalence, lepidopteran host