Widespread but local, only recorded in small numbers each year.
The caterpillars, which are seen from July to September, are up to 65mm long, bright green with purple and white markings. When threatened they can rear up, revealing a red and black 'face' before shooting out formic acid!
Recorded in 63 (91%) of 69 10k Squares.
First Recorded in 1834.
Last Recorded in 2020.