About Coranarta cordigera Thunberg, 1788
Coranarta cordigera Thunberg, 1788 has a wingspan of 21–26 mm. Its forewings are blackish, dusted with pale grey scales especially in the basal and marginal areas; the median area is darker, or even entirely black. The inner and outer lines are deep black. The large reniform stigma is white, with a grey lunule inside it. The orbicular stigma is small, grey, and obscure. The hindwing is yellow, with a broad black marginal border, and a grey costal margin.
There are several known forms of this species. The rare form ab. variegata Tutt has a grey band crossing the dark median area between the two stigmata; the space between the outer and submarginal lines is filled with black to form a fascia, and an additional black fascia follows the basal line. In suffusa Tutt, the entire forewing is black except for the pale marginal area and the white reniform stigma. aethiops Hofm. has an entirely black forewing, with only the stigma remaining pale. carbonaria Christ, from Siberia, resembles aethiops in its upper-side appearance, but the underside of its forewing is yellow with dark marginal areas.
The larva is purplish-red, with a pale yellow dorsal line marked by dark oblique streaks after the fourth segment, which meet on the dorsum. The subdorsal lines are faintly paler than the surrounding body. The spiracular line is yellow, with a black upper edge. The spiracles are yellow, and each is paired with a yellow blotch. Occasionally, the entire larva is blackish, with all of its markings completely obscured.
