Treble Bar

Aplocera plagiata, known as the treble-bar or St. John's wort inchworm, is a moth of the family Geometridae. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. It is found throughout the Palearctic region and the Near East.

This species varies considerably in size (wingspan 37–43 mm) and colouration, but is generally grey with three characteristic dark fascia across each forewing, that resemble a musical 'Staff', giving it its common name. The hindwings are pale grey or buff. Many forma have been described. (See Prout's The Macrolepidoptera of the world)