Family Notodontidae Hodges # 7995
Caterpillar foods: birch, cherry, hickory, maple, willow and other trees (Covell), Black Walnut (personal experience)
Heterocampa guttivitta males have yellow antennae, so they are easy to separate from H. biundata with black antennae. Females of both species have thin, dark antennae, but they can be associated with males to get a probable ID. (Paul John)
I’ve found several of these caterpillars on Black Walnut leaves.
The first caterpillar
9/12/2011 It got much fatter.
I found this second caterpillar at an earlier instar.
9/15/2011 They eat along the edge of a leaf, with their bodies stretched along the eaten edge.
9/15/2011 Great camouflage!