Distribution and Abundance: Common.

Primary Habitat: Woodland.

Flight Period: Single brooded in June and July.

Observations: The gregarious larvae can often be seen in late summer on branches of trees that they have defoliated, especially birch and sallow. The Pitsford Water static light traps show considerable fluctuation in abundance over the decade to 2009: - 2000 - 50, 2001 - 20, 2002 - 8, 2003 - 40, 2004 - 114, 2005 - 181, 2006 - 182, 2007 - 21, 2008 - 10 and 2009 - 19.

L.O.N.: 1907. Almost everywhere. Abundant.

First Record: 1842, Clark.