Kim
Your large green caterpillar is a Cecropia moth caterpillar.
It is one of the large silkworm moths in the Saturniidae family. Below is a website to see the moth that your caterpillar turns into.
The caterpillars feed on foliage of many trees and shrubs including maple, oak, cherry, poplar, ash, beech, apple, boxelder, dogwood, gooseberry, elm, and willow. The moths do not feed, but survive on the energy accumulated by the caterpillar.
This insect overwinters as a pupa, so when the caterpillar is finished eating it forms a silky cocoon that is attached to twigs ...then the moth emerges the next spring.
