Halysidota tessellaris

Life cycle

One generation per year occurs in the north, and two or more occur in the south.

Egg

Eggs are laid in masses on the undersides of leaves.

Larva

Caterpillars are covered with long setae, in tufts. They vary from yellowish and orange through dark gray. Extra long hair-pencils of white, black, and/or orange occur at both the front and rear of a caterpillar. Larval head capsules are bright orange. In the north, mature caterpillars are found from July to frost. Caterpillars frequently rest on the upper surface of leaves, and though not gregarious, they are very conspicuous. They grow to a length of up to 1.75 inches (44 mm). The hairs are urticating and easily dispersed by the caterpillar.

Pupa

Pupae overwinter in gray cocoons laced with larval hairs.

Adults

Wings are light brown. Forewings have bands of beige edged in black. The body is 'hairy' and yellow. The thorax has blue-green lines on its uppersides. Adults are attracted to decaying plants with pyrrolizidine alkaloids. They regurgitate on them, then drink the fluids, and acquire defensive chemicals.

The moth appears very similar to the sycamore tussock moth (Halysidota harrisii) in the adult stage and may be distinguished based on differences in genitalia.

Food plants

Larvae are known to feed on some species of alder, ash, birch, blueberry, chestnut, elm, grape, hackberry, hazel, oak, walnut, willow, and many others. No serious injury to trees has been reported for this late-season feeder.