About Thera cognata (Thunberg, 1792)
This is Thera cognata, originally described by Thunberg in 1792. Its wingspan measures 26–30 mm. The forewings are reddish brown, with darker median bands and basal fields. These darker areas are bordered by black and white crosslines. The hindwings are whitish. Thera cognata is easily distinguished from Thera variata by its strong purple-brown or red-brown gloss. Its hindwing is slightly more glossy than that of Thera obeliscata. The typical northern form of Thera cognata is rather small and generally dark reddish. The form geneata Feisth., which is the prevailing form in the Alps, Transcaucasia, and possibly also the Pyrenees, is larger, somewhat paler, and has a less pronounced red tinge; its ground colour is mixed somewhat with violet or purplish. The aberration ab. perversa Hirschke is a form of geneata found at Franzenshohe, where the basal and median areas of the forewing are lighter instead of darker than the wing's ground colour. The larva of Thera cognata is naked, light green, and marked with white longitudinal stripes.
