[...] In Durham it is widely distributed in most suitable woodland and scrubland sites, where TCD has only found it in places not far from streams, humid conditions appearing to be a necessary condition for the caterpillar to thrive. It is taken regularly in the Upper Teesdale and Hamsterley Forest traps as well as in many places in the central Tees, Wear and Derwent valleys, extending to the coastal denes, but never appearing in the dry limestone quarries where the foodplant often grows quite profusely. Most records refer to the period mid-June to late July. with 29 May 1981 (Witton Gilbert) a[...] being the earliest records for Durham [...].