Abstract
Variation in the tempo of development of larval P. pugio and P. vulgaris reared in the laboratory on diets containing (but not on diets lacking) animal tissue is probably related to the quantity of food available. The rate of development and the frequency of molting may be suppressed by a reduction in the diet. The independence of the frequency of molting from the rate of development makes possible considerable variation in the structure and number of larval intermolts.