At this time of year caterpillars that will become moths and butterflies can be found on trees and bushes. So can cocoons, the next stage in the life of a moth or butterfly. If your boys find a cocoon on a nature ramble, carefully cut off the piece of the branch to which it is attached. Treat it gently as you carry it home. Make a home for it out of an empty, clean ice cream tub with a window cut in it. Cover the window with plastic wrap. In due time, the cocoon will spring forth as a moth or butterfly.