Most butterfly species wait until springtime, just before the onset of summer, to deposit their eggs. Therefore, April and May are the typical months for the metamorphosis of caterpillars into butterflies. However, this is not always the case. During the winter months, several species of butterflies lay their eggs. Even though they have just hatched, the caterpillars don't even bother to eat. They go into a dormant state similar to hibernation and burrow deep into the ground to survive until spring. In the early spring, they metamorphose into butterflies.