Caterpillars are the larval forms of butterflies and moths. They look completely different from their adult counterparts - they've got 8 pairs of legs instead of 3, tiny eyes and no wings. Many changes occur over a caterpillar's lifespan.
After initially hatching, caterpillars are very small. As they eat and grow, they need to moult. Like many insects, their skin does not grow and stretch, so it must be shed. Caterpillars tend to eat their moulted skin so as to not waste any energy.
In between each moult they grow, getting larger and bulkier. Eventually they will moult one last time.
This final moult is what gives rise to the growth of the chrysalis.
