Mecyna mustelinalis is a moth in the family Crambidae. It was described by Packard in 1873.[1] It is found in North America, where it has been recorded from Alberta, Arizona, British Columbia, California, Manitoba, Montana, Nevada, Saskatchewan, Utah, Washington[2] and Yukon.
The length of the forewings is 12.5–16.5 mm.[3] Adults have been recorded on wing from March to August, with most records from July.