About Apterogenum ypsillon (Denis & Schiffermüller), 1775
Apterogenum ypsillon (Denis & Schiffermüller), 1775 has a wingspan of 32–42 mm, and forewings that measure 15–19 mm in length. The forewings are grey, dusted with blackish scales, and have more or less reddish brown suffusion; a dark streak runs from the base below the cell. The inner and outer lines are pale and very obscure. The submarginal line is pale, distinct, and generally preceded by dark marks. The stigmata match the ground colour, while the cell is dark fuscous. The claviform stigma is long and pointed, and often followed by two black streaks extending to the outer line. The orbicular stigma has an irregular shape, and is often elongated below, touching the reniform stigma. The hindwing is fuscous, and often paler toward the base. The rarer grey form, with very sparse rufous suffusion, represents the type; the commoner rufous-suffused specimens are the corticea Esp. variant. ab. nigrescens Tutt is a rare form with blackish forewings. variegata Tutt has purplish blackish colouration; the costa is marked with a series of short black streaks, the orbicular, upper reniform and claviform stigmata are pale, the veins are pale against the dark ground colour between them, giving a striated appearance, and all lines are pale. ab. conjuncta Warren is purplish fuscous, with whitish veins and stigmatal annuli, and the upper two stigmata are strongly conjoined. In orenburghensis Bartel, the ground colour is whitish grey, with darker rufous grey shading, particularly on the cell. The orbicular stigma is large, whitish grey, and prolonged below to touch the reniform stigma, which is dark with a pale ring. The space beyond the reniform stigma is rufous grey, with pale veins crossing it. Below the median vein, the claviform stigma and the area within the median shade are also pale grey. The hindwing has a paler basal half, which shows a dark cellspot and an outer line. The larva is brown, sometimes leaning toward reddish, marked with black on the upper side, with a paler under surface. It has three pale lines along the back, and one pale line low down along each side. The head is pale brown, freckled with darker brown.
