March 24th in  Tohkri village, Lasva parish in Võru County. The butterfly settled on Kristel Vilbaste’s coffee cup

Orange underwing    Harilik kevadvaksik     Archiearis parthenias

Quite rightly the orange underwings are held to be the earliest heralds of the butterfly period. The orange underwing is active in daytime, and it is one of the most colourful representative of its group.

The flight period of the imagos (adult butterflies) starts in March, lasting until the beginning of May.

Where can we see them? They are active where birches grow because the caterpillars  feed on birches. Even though the butterflies are active in the crowns of trees they descend to damp ground to drink.

The wing span of the orange underwing may reach 4 centimetres. In the rest position the brown-patterned forewings cover the orange rear wings. Identification is not difficult in flight: the orange rear wings are the same colour on both sides.

Photo: Dumi, Wikimedia Commons