A butterfly starts life in the form of round or oval eggs laid on the leaves of plants. The shape of the eggs will depend on the butterfly that lays them. When the egg finally hatches, a larva is formed and that is what we call a caterpillar. A caterpillar only eats at this stage and will mostly eat the leaf of the plant they were born onto. So it is important that the mother butterfly pick the right plant to lay its eggs. The caterpillar does not stay on this stage for long they grow by shedding off their outer skin into the pupa stage. Finally, when the caterpillar has done all its forming into the pupa a butterfly will emerge with soft wings folded against its body.