Key to the L. subdita species-group

1. Distal forewing mottled with patches of dark scales; fringe checkered; occurring in northeastern North America............................................. L. subdita

– Distal forewing smooth with inconspicuous dark areas limited to the subterminal line; fringe nearly unicolorous; occurring in western North America 2

2. Distal claviform spot a black bar; occurring in Rocky Mountains south of Beartooth Plateau on Montana-Wyoming border..................... L. conjugata

– Claviform spot without a black bar; occurring north and west of Beartooth Plateau...................................................................................... L. fergusoni