Hitched Arches

Adult: forewing ground color dark gray or black, providing good contrast against the following four areas of white: a small basal patch, small orbicular spot, large reniform spot, and broad wavy terminal line; reniform spot with wavy basal margin and curved black line in center; all-dark melanic specimens fairly common in Ontario [Jeff Crolla, per. com.]
hindwing gray, darker at outer margin
Larva: two forms - either light green or light brown; both forms have darker diagonal markings dorsally and ventrolaterally, and thin whitish dorsal line; head dark with 3 white dorsal lines; 8th abdominal segment humped, with dark lateral patch