The population dynamics of the Colorado potato beetle,Leptinotarsa decemlineata(Say), were studied in central Mexico in 1987 and 1988. During the June-October rainy season, three generations were observed in 1987 and two in 1988. Predation and parasitism were found to be important mortality factors, particularly late in the season, contributing to generation mortality as high as 99.8%. Time series cross-correlation was used to estimate synchrony of Colorado potato beetle eggs with predators. Predators, including asopine pentatomids, carabids, thomisid spiders, and coccinellids, were abundant and well synchronized with developing Colorado potato beetle late in 1987, corresponding to the period of highest mortality.