A linear relationship was observed between ovarian developmental rate in Coccinella septempunctata L. and five constant temperatures (14-30°C). The estimated lower temperature threshold for follicle development was 13°C. Development of follicles to maturity (egg chorionation) required 833 degree-hours (° H > 13°C). A five-stage rating system to describe ovarian development in C. septempunctata was based on the length of the terminal follicle, number and shape of developing follicles in each ovariole, and presence of yellow color in the terminal oocyte. In 60-70% of females at each temperature, follicle development in relation to female age (time) followed a sigmoidal pattern. This sigmoidal curve had three phases, a previtellogenic or lag phase, a vitellogenic development phase characterized by rapid increase in follicle length, and a postvitellogenic or chorionization phase characterized by a constant follicle length. An equation to predict either the proportion of gravid females on the basis of degree-hour accumulations, or the degree-hour accumulations on the basis of proportion of gravid females, was developed.