I found this caterpillar on 6/2/09Â feeding on American Hazelnut leaves (Corylus americana).
Top view of larva
On 6/15/09 it pupated in a silk nest on one of the hazel leaves.
This is the pupa removed from the nest, with the old caterpillar skin on the left.
On 7/6/09 the adult emerged.
Pupa casing after emergence
According to David Wagner in Caterpillars of Eastern North America, Haploas eat plants in the sunflower and borage families in early instars.Â They over winter as larvae, and after hibernation, they may eat many other plants.Â They have only one generation per year.
Buffalo County, Wisconsin