The Large Blue Butterfly is the largest of our native blue butterflies. It is one of the rarest butterflies in England. It became extinct in 1979, but was reintroduced in Cornwall in 1983. As a butterfly, the Large Blue Butterfly lives on average for only about four to five days.

Large Blue Butterflies lay their eggs on thyme and marjoram flowers. A pinkish coloured caterpillar emerges from each egg. After about two to three weeks the caterpillar falls to the ground and allows itself to be found by red ants which take the caterpillar to their nest. The caterpillar stays in the ants nest for about eight months and then forms a chrysalis by spinning a silk case around itself. The chrysalis is just under the surface of the ground. Inside the chrysalis the caterpillar transforms itself into a beautiful Large Blue Butterfly which is then escorted outside by the red ants.

The Large Blue Butterfly is easily recognised by its sea-coloured blue wings edged with a dark blue and white border. Its forewings are speckled with bold dark spots. It can be found on heaths, sand dunes and hillsides around June or early July.