105171 Common Blue Polyommatus icarus Wingspan 32mm. Britain’s commonest and most widespread blue butterfly. Adult male has blue upperwings; female’s are usually brown (sometimes tinged blue in the middle) with submarginal orange spots. Underwings of both sexes are grey-brown with white-ringed dark spots and orange submarginal spots on hindwing. Flies April–September in two or three successive broods. Larva feeds on Bird’s-foot Trefoil and related plants. Common in grassy places where larval foodplant grows.