Abstract
Opostegoides minodensis (KUROKO) (Lepidoptera: Opostegidae) is one of the cambium miners which cause pith flecks in the wood of the Japanese white birch, Betula platyphylla SUKATCHEV var. japonica (MIQ.) HARA, Hokkaido. Eggs were singly laid on the undersides of leaves, and were mostly located on the medial part of a leaf. Upon hatching, the larva bored into the leaf and reached a branch, mining through the vein and the petiole. After entering into the branch, the larva moved toward the base of a branch or a stem in a fairly straight course. Subsequently, the larva mined in a slender elliptical course, creating 4 or 5 ellipses. The final instar larva invaded the final ellipse of the mine made before the final molt and mined it nearly circular mine. The mature larva bored a long oval exit hole in the bark and dropped to the ground. Larvae mainly mined in branches and in the stems within crowns. In stems, they were most abundant at 2 to 3m below the tops. This was probably caused by the eggs' locations on leaves and the limited larval movement (only 1m) from oviposition sites toward the bases of branches or stems.
