The rearing of Papilio polytes Linnaeus was made individually on citrus leaves under a laboratory condition without controls of temperature, humidity and illumination. The largest widths of exuviae of head capsule were measured for the same individual through its development. The results of analysis of variance of the measurements showed that the increase of log-width of head capsule(Y) in successive instars(X) of male and two types of female(f. madane and pammon) have been described by quadratic of Gaines and Campbell rather than by Dyar's linear equations.