The Elm sphinx, (Ceratomia amyntor), sometimes called the Four-horned Sphinx, is a North American species of moth in the Sphingidae family. It has a wingspan of 3¼ - 4½ inches (8.2 - 11.5 cm). As the name suggests, the larvae (caterpillars) feed on elm trees (Ulmus), but they can also be found feeding on birch (Betula), basswood (Tilia), and cherry (Prunus). When the caterpillars are ready, they crawl to the bottom of the host tree, where they crawl underneath the soil and pupate and may overwinter underground if late enough into the year.