Aplocera praeformata, known as the purple treble-bar, is a species of moth in the family Geometridae.
This species is present from the Iberian Peninsula and France, through Western Europe, over Central Europe, to Russia. Its northernmost range is southern Finland and the Baltic States. The subspecies Aplocera praeformata urbahni is found in Greece. In the Alps it is found to heights of up to 2,000 meters.
