Robson says, 'a local species, but sometimes plentiful where it occurs'. We now know that it is much more widespread than Robson indicated. It does, however, avoid coastal habitats [...] The caterpillar feeds on Heath Bedstraw and the moth is found wherever it grows. This incorporates most heath and grassy moorland [...] but woodland and, in the west, hedgerows are all encompassed. Sometimes, when conditions are suitable, the species swarms. TCD has [...] had the pleasure of encountering such mass emergences [...] on 9 August 1974 when the [...] phenomenon occurred along the North and South Grain Becks on Pikestone Fell.