156981 Green Hairstreak - Callophrys rubi - Upperwing (top) Underwing (bottom) Wingspan 25mm. A small butterfly whose buzzing flight is hard to follow. Adult seldom reveals brown upperwings; underwings are bright green and an extremely good match for the leaves on which it rests. Flies May–June. Larva feeds on gorses, Heather and trefoils. Locally common on heaths, cliffs and downland scrub.