ニカメイガ卵塊個体群の研究に適用しうるサンプリング法

During the three years 1957-1959, the writer made observations on the egg mortality of the rice-stem borer, Chilo suppressalis WALKER, in its first brood, in a paddy field at Nogi, Matsue City. Every observation day in the first two years, a new map was drawn showing the location of rice-bunches which bore, on that day, egg masses not yet hatched or just after hatching in a plot established in the field. In 1960, a map of the same kind was made only once.
The writer intends, in this paper, to investigate whether some of these maps answer the following two questions:
1) Whether the sequential sampling technique is applicable to classifying given paddy fields according to population levels of egg masses existing in them.
2) Whether a kind of the spacing method as proposed by MORISITA (1957) is adequate for estimating the population density of egg masses in a given paddy field.