Best time to see: Jul to mid Aug

Key facts

Distinctive chequered black and white butterfly

Habitat: tall unimproved (i.e. not ploughed or fertilised) grassland, commonest on chalk and limestone

Restricted mainly to southern and western Britain with scattered colonies elsewhere, including a very few in Essex

Recognition

Clear cut black and white chequered pattern on upperwing, less distinct on underwing, which also has eyespots

Lives in colonies with strictly defined boundaries

Flaps lazily above the grassheads, alighting often to bask or feed on tall flowers like knapweed; wingspan c.5 cm

Lifecycle

Spherical white eggs dropped singly into patches of tall grass in July/August

Caterpillars hibernate almost right away and pupate when full grown the following June, adults emerging in July

Green or pale brown caterpillars hide by day and climb grasses at night to feed