My stepdaughter found a caterpillar today. He's about 2 to 2-1/2 inches long, a dark green and has 3 orange triangular markings on the rear end of his body. We live in northern Indiana, if this helps any.

Try this site

Discover Life -- Caterpillars identification guide & checklist (http://pick4.pick.uga.edu/mp/20q?guide=Caterpillars)