The ground colour of the wings of the male is a dull yellowish grey, and that of the female greyish white. In both cases the wings are crossed by irregular dark brown bands. The fringe is barred alternately with white and dark brown, and the whole of the ground tint between the above-mentioned bands is thickly dotted with dark brown. The female is generally smaller than the male.
The caterpillar is very variable in colour, but is generally reddish brown, ochreous brown, or greenish, with a light line along the spiracles, and a series of lozenge-shaped spots on the back. It feeds on trefoils (Lotus corniculatus and L. pilosus) and various other plants that grow on heaths.
The Bordered White (Bupalus piniaria)
The male of this species is boldly marked with yellowish white and dark brown, the arrangement of the two colours being shown in [fig. 190]. The female is very different in general appearance. Her wings are of an almost uniform orange or yellowish-brown tint. The fore wings are darker near the tip, and there is generally a darker transverse band across the centre.
The male may often be seen flying in the sunshine among the branches of fir trees during May and June, but his mate is rather less active, and is generally to be secured by beating the branches.
The caterpillar is pale green, with whitish stripes and yellow spiracles. It feeds during August and September on the leaves of the Scotch fir (Pinus sylvestris).