Technical description and variation
The wingspan is 27–34 mm. The length of the forewings is 12–15 mm. Forewing smooth, unspeckled green, the markings black and prominent: the claviform (club-shaped) and orbicular (round) stigmata coalescing to form a blotch; ab. ''par'' Hbn. is grey green, with darker green dusting; the black markings obsolete. — ab. ''impar'' Warr. is green dusted with black or rufous; the lines more or less obsolete: the green colour fades more quickly than in typical ''muralis''; this form occurs only at Cambridge, where the type form is nonexistent. Four further aberrations have been differentiated; ab. ''viridis'' Tutt, rich green, without black or grey dusting; ab. ''flavescens'' Tutt, like the type, but with the green changed to yellow, even in bred specimens; ab. ''pallida'' Tutt, with typical markings on a whitish-grey ground colour; and ab. ''obscura'' Tutt, dull brownish grey, with the markings obscured and without any trace of green; all these forms are found on the coast of Kent and at Queenstown in Ireland.Biology
The moth flies from June to September depending on the location. Larva dark grey with a greenish tinge: dorsal line broadly white, sometimes interrupted; a pale line above feet. greenish tinge: dorsal line broadly white, sometimes interrupted; a pale line above feet. The larvae feed on various