wingspan about 21 mm, based on specimen by Jim Vargo at MPG
Adult: forewing orangish to light brown with zigzag AM line and jagged PM line that includes a large projecting "tooth" near the inner margin; ST line jagged and more diffuse than PM line; outer part of median area with dark diffuse blotch, and inner part with smaller dark spot; hindwing light gray with yellowish shading in outer half, dark discal spot, and dark PM and ST lines; adults rest with their forewings touching, hiding the hindwings.
Larva: body pale greenish-yellow with dark dorsal line and subdorsal spot on each abdominal segment; head brownish.
Quebec to British Columbia and all of United States, south to Amazon basin
marshes and pondsides where foodplants grow
adults fly from May to September in the north; earlier in the south
a mass of up to 60 eggs is laid on upper surface of leaf of hostplant, and covered with an amber-colored material; young larvae attach themselves to the leaf by thin silken strands, which prevents them from becoming dislodged by wind or wave action; mature larvae are often covered entirely by a loose silk net, and entire portions of a leaf may be rolled over the larva; mature larvae tunnel into the leaf petiole and form a burrow where pupation occurs; adults emerge from previously-formed exit holes in the petiole. - This information is from a defunct US Army webpage which as of 2019 is still accessible at Archive.org here
. The same information found in Center et al. (2002)(1)
European Corn Borer
) forewing lacks a large "tooth" in lower part of PM line, and its median area is usually darker, giving the wing a bicolored appearance