Abstract
In order to estimate the adult population of the melon fly, Dacus cucurbitae, the mark-recapture method was applied in an area of the northern part of Okinawa Island. From the calculations based on a modified JACKSON'S negative method, the density of mature male melon flies in an area with typical vegetations in the northern part of Okinawa Is., a combination of Castanopsis (Shiia) cuspidata forest and Pinus liutchuensis community, was estimated to be 5.5 per ha, at their most abundant season. The total number of the mature male melon flies in Okinawa Is. and adjacent islets at the same season was estimated to be ca. 38, 000, 000, using data obtained by the present study and ICHINOHE et al. (1978) who estimated the density in the southern part of Okinawa Is. as being 622 per ha.
