Oak Eggar Moth Lasiocampa quercus

Oak Eggar moth My thanks to Darren Parsons for the above photo of a male Oak Eggar moth readying for flight.
Oak Eggar moth My thanks to Luke Amos for the above photo of a female Oak Eggar moth.
The male Oak Eggar, as above, is a dark chestnut brown with pale yellow-brown markings. He flies by day and is a large moth but much smaller than the female. The much larger female is light brown with lighter brown markings and flies from dusk. Different sources quote substantially different ranges of wingspan from 30/45/68mm for the male to 40/75/96mm for the female. The northern form, sometimes called the Northern Eggar, is larger than the southern. UK flight time also varies from May-Jul in the north where a single generation takes 2 years and Jul-Aug in the south where there is a new generation annually.
Oak Eggar moth Thanks to Darren Parsons again for the above photo of an Oak Eggar caterpillar.
Despite the name Oak Eggar (and Latin name quercus - oak) the caterpillars are not found on oak but eat heather, bramble and other plants. The name is said to be because its cocoon looks like an acorn.