Moths have four stages to their life cycle: embryo, larva, pupa and imago, or more simply egg, caterpillar, cocoon and adult moth. Butterflies have the same life cycle, but the pupa of a butterfly is called a chrysalis. In the pupal stage moths wrap themselves up in a hard cocoon and lay still for a couple weeks to several months while they transform into a moth. At the end of this period, they emerge into an adult moth.
Wrapping Itself Up
A moth caterpillar will eat and eat until it is has moulted, or shed its skin, about four times. It grows much larger during this period and eats a lot. When it is ready, the caterpillar will find a good location in the tree or on the ground. Some will wrap themselves in a leaf, others will hang from a limb. They will then spin a hard cocoon around themselves. This hard cocoon will protect them while they metamorphose, or change into an adult moth.
After the moth finishes wrapping itself up in its hard cocoon, it will change into a pupa. While in the pupal stage the moth does not move. This stage can last for only a few weeks or for several months. Some moths can stay in the pupal form for years until the conditions are right for their emergence.
When the conditions are right and the adult moth has formed, it will emerge from the pupal form. The case splits open and the adult crawls out, it spreads its wings and prepares to fly off and find a mate.
If the conditions are not right the pupal stage will continue until the conditions are right, or the pupa dies. Moths will overwinter, staying in their pupal stage for several months until the weather warms. Some will stay in the pupal form for years in order to live through a drought. After the drought is over and the conditions are right, the moth will emerge to look for its mate.