In insect herbivores, particularly those with sedentary developmental stages in their life histories, such as leafminers that spend larval/pupal stages within a leaf, the spatial distribution on plants should be determined in response to heterogeneity in several factors such as vulnerability to enemy attack. Their feeding track called mine is white, contrasted with the green of leaves. Restricted mobility during their mining stages and the conspicuousness of the mines should expose the leafminers to the high risk of parasitism (Connor & Taverner 1997). In lepidopteran leafminers, the species utilizing lower leaf surface as mining site have developed widely over the phylogenetic tree, compared to those utilizing the upper surface (Lopez-Vaamonde et al. 2003). Leafminers making mines on the lower leaf surface may be less recognized by parasitoids and thus be more advantageous in the avoidance of parasitism than those on the upper surface. So, we examined the relationship between parasitism and the within-leaf distribution of the lepidopteran leafminer Phyllocnistis sp., which can utilize both the upper and lower leaf surface of the Japanese privet Ligustrum japonicum, and then discussed whether the prevailing use of the lower leaf surface in this species may be attributed to an interaction with parasitoids.