The Interrupted Dagger moth has a wingspan of about 1.5 inches (3.5 – 4.2 mm). The forewing is light to medium gray with a basal dash that merges into an indistinct, incomplete antemedial line. The white-edged postmedial line is crossed by a thin, black anal dash. The fringe is checkered with dark scales between veins. The hindwing of the male is dirty white darkening near the outer margin. The hindwing of the female is light gray with a faint postmedial band. The caterpillar is red, white and blue-gray with paired middorsal red spots. It has a broad white subdorsal stripe. The head is dark reddish-brown. It grows to 1 5/8 inch (4 cm).