Factors affecting the mortality ofColeomegilla maculata lengiTimberlake were investigated at Guelph, Ontario from 1976 through 1978. It was found that most of the overwintering mortality of caged beetles occurred at the end of the winter. Parasitism byPerilitus coccinellaeShrank reduced survivorship of overwintering beetles. There was no significant difference found in overwintering mortality of beetles caged at three different densities. Predation of eggs ofC. m. lengiwas 44.8 and 48.6% in 1976 and 1977, respectively. Stage-specific mortality for the coccinellids of the first generation in corn (primarilyC. m. lengi) at Guelph calculated for the period from egg to pupa was 93.8% in 1977. In 1978, mortality from egg to pupa ofC. m. lengiwas 95.4%.C. m. lengidisplays a type IV survivorship curve of Slobodkin.