June to August sometimes with a partial second generation in the south from September to November. Common throughout Britain. The adults come to light in large numbers and can be one of the most common species in a moth trap during late summer.

Although they can be quite variable in colour they are easily recognised by the large and conspicuous oval and kidney mark and a W-shaped mark near the outer edge of the forewings. There is a dark melanic form f. aethiops which is more frequent in the north.

When the larvae are small they feed on flowers and seeds and when older they feed on roots and stem bases from within a chamber among grass roots where they will overwinter.