In prior studies, critical points have been found in the interaction between exogenous (food) and endogenous (hormonal) control of the larval development of decapod crustaceans. One of them was termed "point of reserve saturation" (PRS). If it has been passed under conditions of sufficient availability of food, decapod larvae may complete their moulting cycle and develop, independent of food to the next instar. In the present investigation the PRS and the moulting cycle were studied simultaneously in first instar larvae on nine decapod species belonging to eight families and four higher taxa (Caridea, Macrura, Anomura, and Brachyura). The experimental results suggest that the PRS was in general near the transition between stages C and D sub(o) of Drach's classification system, independent of the species, instar duration, and temperature.