About 7 days after being laid, the eggs hatch. Small larvae mine the leaf sheath for about a day and then move to the soil to feed on the roots, where they stay through four larval instars. The legless larvae are milky white with light brown heads and have spinelike projections on their backs to pierce the roots and obtain oxygen. When their growth is completed, larvae pupate in mud-coated cocoons that they attach to the roots of rice, sedges, or various grasses.