Caterpillars in Your Yard and Garden
Achemon sphinx caterpillars, Eumorpha achemon, are present from early summer to fall. They produce one to two generations per year.
Also called the grape sphinx, developing and full-grown achemon sphinx caterpillars are green, yellow-brown or brown. The horn at the end of the body is long and slender and is lost with the last larval molt. On the sides of the abdomen are oblique white bars that appear to be partially subdivided unevenly into three sections; the spiracles are found within the lowest (and largest) compartment. Full-grown caterpillars are 2.5 to 3.5 inches long. Preferred host plants are grapes (wild and domesticated) and Virginia creeper.
About the family
Many caterpillar species in the Sphingidae family are referred to as "hornworms" because they have a conspicuous horn or spine on the top of the last abdominal segment. The bodies of these caterpillars are usually free of hairlike setae and smooth except for shallow wrinkles in each segment. Adults are referred to as "sphinx," "hawk," or "hummingbird" moths. They are fast, strong fliers with a rapid wing beat and often hover in front of a flower to feed on the nectar in much the same manner as a hummingbird (and superficially they look like a hummingbird too!). The name "sphinx" is probably in reference to the sphinx-like position that some of the caterpillars assume when disturbed. Some common vegetable, tobacco and other plant pests belong to this family of caterpillars.