The smeared dagger moth adult has a wingspan of Шаблон:Convert.[1] The forewings have a mottled gray appearance, with orbicular and reniform spots on each dorsal surface that are incompletely outlined and indistinct.[1] Smeared-appearing dark wedge spots are present along the postmedial line with their apices pointed inward.[4] There is a terminal line of dark spots on the forewing.[1] The hindwings are white and also have small dark spots along their terminal line.[1]
The larva is a caterpillar up to Шаблон:Convert long that bears numerous tufts of irritating setae on wart-like protuberances along its thoracic and abdominal segments.[1] There are bright yellow blotches in the shape of carets (inverted "V" shapes) between the laterally-positioned spiracles.[1][5]
Habitats include bogs and coastal marshes in the Pacific Northwest[4] and wetlands, forests and meadows more generally.[6] Individuals have been collected in boreal forests in Canada.[6]
The smeared dagger moth has one to two generations per year.[1][8] In the coastal plain of North Carolina, adults can be seen beginning in early March through late June and again from mid-August until early October.[8] Caterpillars may pupate within folded leaves of their host plant.[9] Overwintering occurs as pupae.[1]
