Larvae of the beetle Trogoderma glabrum undergo partially reversed development when deprived of food and water. Retrogressive larval ecdyses occur, and the larvae become diminished in size and weight. Given food, the larvae regrow, ecdyze, and regain their previous degree of maturity. Repeated cycles of retrogression and regrowth are possible. Although larval in form and organ differentiation, repeatedly retrogressed insects display a physiological deterioration suggestive of aging. A deterioration of the ability to regrow is accompanied by increasing fat body polyploidy.