Scanning electron micrograph of a hatching egg of the large white butterfly, Pieris brassicae, showing the head of the caterpillar breaking through the shell. The eggs are laid in large groups, usually on the undersurface of leaves of nasturtiums & Crucifer crops such as cabbage, broccoli, swedes etc. These caterpillars (larvae) hatched in early September. They will overwinter as pupae emerging in May as adult butterflies. The young caterpillars feed exclusively on the cuticle of the leaf until after the first moult, when the diet expands to include the whole leaf. The voracious appetite of these pests can lead to the defoliation of whole crops. Mag:X300 (10x8).