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Quite variable in the extent and colouration of wing markings. Reddish brown to brown-grey ground colour with dark AM and PM lines, PM line often bordered proximally with reddish brown. Discal spots black and prominent. Forewing apex often slightly falcate. Very similar to M. warnerae, but overall colour has reddish-brown overtones and patches, while warnerae is entirely brownish-grey. M. warnerae has a smoother, straighter PM line than M. duaria. McGuffin (1987) also states that the presence of dark shading on the inside of the PM line distinguishes warnerae from duaria, but this trait is found in both species in Alberta.

This species is often common in deciduous forest and shrubland, from prairie riparian forest to the central boreal region. The larvae are stout and mottled brown (Wagner et al. 2001), reminiscent of a cutworm (Noctuidae) rather than the typical geometrid body-plan of mimicking twigs. Wagner et al (2001) note that mature larvae are virtually never collected from trees or shrubs; Prentice (1963) notes a similar situation. Larvae may feed only at night and rest on tree boles or on the ground during the day (Wagner et al. 2001). McGuffin (1987) notes that eggs are laid without adhering to any substrate, and these would undoubtedly end up on forest floor. This species may spend most of its time among leaf litter rather than depending on crypsis on host branches like many geometrids.