The Blackneck Lygephila pastinum
Wingspan 37-42 mm.
In Britain, this moth has only one generation, flying in June and July, but it is double-brooded on the continent.
Occupying woodland and marshy areas, it is locally common in the southern half of Britain, with only scattered occurrences further north.
The species overwinters as a larva, which feeds mainly on tufted vetch (Vicia cracca).