In recent days a number of migrant insects have arrived in Britain, including a rare butterfly, the Scarce Tortoiseshell (also known as the Yellow-legged Tortoiseshell). So far they have been seen at Queen's Hills, Burgh Castle and a private site near Wells, but it is expected that more may arrive (or already be here!). So if you see a Tortoiseshell butterfly that doesn't look like the common Small Tortoiseshells then it is well worth a second look! To get the record accepted you will probably need a photo showing the legs in order to rule out Large Tortoiseshell (itself a rarity). The county butterfly recorder would be very interested in any sightings (as would I, as I'm yet to see one!).
If you want to see what they look like then just type 'Scarce Tortoiseshell' into google, or look here: