Beautiful Yellow Underwing

Anarta myrtilli, the beautiful yellow underwing, is a moth in the family Noctuidae. The species was first described by Carl Linnaeus in 1761. It is found in most of Europe including Scandinavia, Britain, France, Germany, Switzerland, Spain, Portugal, Italy, and Russia.

The wingspan is 20–22 mm. Forewing dull dark fuscous purple, with the lines slightly paler; the stigmata obscure; a subtriangular whitish blotch on base of vein 2; hindwing orange with broad black terminal border; the costa and inner margin narrowly black and the base of wing often smoky blackish; this, the type form, occurring in Sweden, the north of England and Scotland, and other northern localities is very different from the usual bright red form, which is the ab. rufescens Tutt. In this the forewing is a mixture of bright red, and olive brown or olive yellow; the transverse lines being more or less strongly whitish, the stigmata red brown with pale rings, and the white spot on vein 2 distinct; ab. peralbata ab. nov.