The Drinker is distinguished from other large eggars by outer cross-line on forewing which runs diagonally to wing tip, and the two central white spots.
We have found many Drinker caterpillars on our field trips but this male moth, which we found in Glen Feochan on Tuesday 26th June 2012, is the first I have seen. Quite a stunning example and well worth the wait.
Photo courtesy of Richard Wesley