Abstract
Under various population densities, newly-hatched larvae of the cupreous chafer were reared in outdoor pots with mixture of fallen leaves and natural soil throughout nearly all the larval period. Head widths of larvae were measured at regular time intervals. From the frequency distribution of head width in each initial population density, it was assumed that the number of larval instar was three, and that the boundary values of head width for separating each larval instar were not varied with different initial densities, although slight differences in the head width distribution were found between the lower initial population density and the higher one in each larval instar, especially in the second instar, i.e., the mean value and the variance of head width decreased with the increase of the initial density. Although the development of the larvae was more rapid in higher initial densities, the effect of initial larval density on the larval growth and development was not considered to be significant.
