The spatial and temporal larval distributions of the newly recognized potential pest of boreal forests,Korscheltellus gracilis(Grote), are presented. Larvae were collected from 17 of 20 areas in the Green Mountain National Forest, Vermont, and highest densities were at elevations>1,000 m. On Camels Hump Mountain (Huntington, Vt.), larval density during the summer of 1987 was approximately 440,000 ± 36,000 per hectare. Changes in density between May and August 1987 were not detected. Larvae were clumped in space and most abundant in the upper 9 cm of soil. Data from head capsule measurements suggest at least six instars.