Marbled White

From www.butterfly-conservation.org

The second of the three butterflies was the Marbled White, Melanargia galathea. I saw this again today, this time up on the Downs above Lewes. A few Small Skippers were also about and plenty of tomorrow's butterfly.
This is an eye-catching butterfly that is hard to confuse with the 'whites'. It is in fact a member of the Brown family, Satyridae, which has been subsumed into the family Nymphalidae. All members of the Nymphalidae have two pairs of functional legs, the third pair having become vestigial.