A butterfly lays eggs on the leaves of a plant. These eggs hatch and young ones called larvae or caterpillars come out of the eggs. The caterpillar starts feeding on the leaves and starts to grow. It sheds its skin several times so that it can grow. Once the caterpillar is big enough, it stops eating. It then forms a protective layer around itself. This stage is called chrysalis or pupa. The caterpillar remains motionless in the cocoon for about 10-15 days. Inside the cocoon, the caterpillar undergoes a series of changes. After about 15 days, a beautiful adult butterfly emerges out of the cocoon. These series of changes in the life cycle of a butterfly is called metamorphosis