Female Homalodisca coagulata (Say) were collected from October 2001 to February 2005 from citrus at the University of California, Riverside. Between 5 and 20 females per sampling date were dissected, and each was assigned an ovarian rank: previtellogenic, vitellogenic, or postvitellogenic. Ovarian ranking was used to characterize H. coagulata reproductive activity. Results of these dissections revealed consistent annual patterns in the proportion of previtellogenic females present in this field population. These patterns indicate that there are two distinct generations annually, with an occasional third generation. A time-dependent model of H. coagulata vitellogenesis cycles in Riverside, CA, was developed, which makes it possible to predict the appearance of the subsequent generation based on previous observed peaks in the proportion of vitellogenic females.