Two cultures (F9 and F15) of adult boll weevils (Anthonomus grandis Boheman) were caged in a temperature-and humidity-controlled room in trays containing cotton squares placed in moistened sand under a low-pressure mercury-vapor ultraviolet light. Another culture (F1) was caged on squares on drier sand under a high-pressure mercury-vapor ultraviolet light. All weevils were fed fresh debracted squares changed daily. Survival data plotted for the three cultures approached the typical sigmoid or semirectangular curve characteristic of an animal population having a senescence. Longevity was variable, and depended upon sex, culture, and holding conditions. Greatest longevity was demonstrated by male weevils from Mexico with a mean of 121.5 days and a maximum of 199 days.