Lophocampa caryae

Caterpillar (top view)

The larva, a caterpillar, is completely covered in long, hairlike setae arranged in spreading tufts. Most are white, but there are black tufts along the middle of the back, and four long black hair pencils, two near the front, and two near the back. There are black spots along the sides, and the head capsule is black. The hairs cause itchy rashes (contact dermatitis) in many people, particularly those prone to allergies, and may resemble exposure to urushiol.[4] They are microscopically barbed and may rarely cause serious medical complications if they are transferred from the hands to the eyes,[5] but in over 350 documented cases, most were asymptomatic within 24 hours, and none involved anaphylaxis.[3]

The later-instar caterpillars are seen between July to October.[4] They feed in groups of about 100 or so in the early instars,[4] skeletonizing leaves. Older larvae are solitary. They grow up to 4.5 centimeters long before pupating. Larvae primarily feed on hickory, pecan, and walnuts, but will also eat ash, elm, oak, willow, and other plants.[4] They may occasionally cause local defoliation of nut trees, but high densities do not last long enough to cause significant damage.[6]

The cocoon is loose and has setae woven into it. It overwinters in the leaf litter.[4]

The adult moth flies in May and June. The forewings are yellowish-brown marked with white splotches, reminiscent of stained glass. The hindwings are mostly white. The body is hairy and pale brown.[6]