Four Horned Sphinx Caterpillar

Unknown caterpillar
September 3, 2009
Hi, I found this really weird looking caterpillar in my birch tree. I have never seen anything like it in my life. It is green with 2 sets of horns toward the front of its head and has 1 horn at the end of its body. It blends in with the leaves and has what appears to be a leafs vein running up it’s back. I searched for something like this online and the closest thing I found was the lime hawk moth caterpillar. Is that what this is?
Denise-MA
Massachusetts

Dear Denise-MA,
According to Bill Oehlke’s wonderful website, the Four Horned Sphinx, Ceratomia amyntor, is also called the Elm Sphinx, and its food plants include:  “Elm (Ulmus), birch (Betula), basswood (Tilia), black locust (Robinia pseudoacacia) and cherry (Prunus).  There are chocolate-brown to orangey-brown, sometimes with a pinkish tint, and green forms of the larvae. The common names are derived from foodplants (Elm Sphinx) and the structure (Four-horned Sphinx) of the larva.”  We are impressed that you were able to locate this well camouflaged Four Horned Sphinx Caterpillar that matches the leaves of the birch tree so well.  We are copying Bill Oehlke on this response so he can add your sighting to the comprehensive data he is compiling on species distribution.