The Glossy Black Idia has a wingspan of about 1.5 inches (24 – 36 mm). The forewing is shiny, sooty brown with a pale band beyond the Subterminal Line. The jagged Antemedial and post medial lines are edged with pale yellow. The hindwing is pale grayish brown with 2 faint lines crossing it. The larva is smoky gray with yellow-orange hornlike projections the length of the dorsal side of the abdomen. The head is black. It grows to nearly one inch long.