Distribution and Abundance:  Common.

Primary Habitat:  Woodland.

Flight Period:  Single brooded in March and April.

Observations:  A range of variably coloured and marked forms occur in the county and ab. immaculata, in which the black twin-spots are absent, is not uncommon. I have found caterpillars of this species a number of times by day in June secreted in bark crevices on oak.

L.O.N.:  Undated. Castle Ashby, near Peterborough.

First Record: 1859, Sturgess.