I live in Colorado and spotted this caterpillar on a Patterson Aster (Machaeranthera pattersonii) and have been unable to identify it? Could you help?
We would love to help. This is a Brown Hooded Owlet Moth Caterpillar, Cucullia convexipennis. We do have one photo on one of our caterpillar pages, but the coloration is a slight variation. They feed on asters as well as goldenrod.