Wingspan: 55–60 mm
Flight period of butterflies: Adults emerge at the end of June and are active into July, then they rest (diapause) and fly again in autumn; they overwinter in hollows and cracks and are the first butterflies that can be observed during the first spring thaws
Larval host plants: common buckthorn (Frangula alnus), species in the genus goat cherry (Rhamnus)
Brimstone (Gonepteryx rhamni) is a large butterfly with distinctly pointed wing tips. Because of this, the butterfly at rest with its wings closed resembles a dry leaf. Its wings are uniformly colored, only in the middle of the forewings and hindwings there is an orange patch. The male has lemon-yellow wings; the female's wings are pale lemon-yellow-greenish and resemble the color of freshly squeezed lemonade. The body is densely covered on the upper side with long, gleaming white-silvery hairs, and the color of the underside of the body and legs matches the color of the wings.
Brimstones fly along the edges of forests and through sunny woods where their larval host plants occur, as well as in open dry or damp grassy areas scattered with shrubs. They occur from the sea to high mountains, where they are found even at elevations above 2,500 m.
