Arcigera flower moth (Schinia arcigera) is common and widespread across North America from the east coast to the Rocky Mountains. In Minnesota, it is found from late July to mid-September in fields with asters.

It is active at night and is attracted to light, but can be also found taking nectar on flowers during the day.

This is a small owlet moth. The adult is about ½″ long and has a wingspan of ⅞″ to 1″. It is distinguished from similar moths by dark brown and pale brown coloration, and by a white, smoothly curved, broadly S-shaped postmedial line.

http://www.minnesotaseasons.com/Insects/arcigera_flower_moth.html