Ross Hoddinott / Holly blue butterfly (Celastrina argiolus) resting on Ivy (Hedera sp), Broxwater, Cornwall, UK. April.

Jussi Murtosaari / Holly blue butterfly (Celastrina argiolus), female, Finland, June.

Bernard Castelein / Holly blue butterfly (Celastrina argiolus) Brasschaat, Belgium

Bernard Castelein / Holly blue butterfly (Celastrina argiolus) Brasschaat, Belgium

Sue Daly / Holly blue butterfly (Celastrina argiolus) on heather, Sark, British Channel Islands, August.

Sue Daly / Holly blue butterfly (Celastrina argiolus), Sark, British Channel Islands, August.

Sue Daly / Holly blue butterfly (Celastrina argiolus), Sark, British Channel Islands, August.

Kim Taylor / Holly blue butterfly (Celastrina argiolus) male at 'salt lick' on peat. Surrey, England, UK, July.

Rod Williams / Holly blue butterfly (Celastrina argiolus) male, Brockley Cemetery, Lewisham, London. May.

Rod Williams / Male Holly blue butterfly (Celastrina argiolus) on Creeping thistle flower, Brockley Cemetery, Lewisham, London, England, July.

Rod Williams / Holly blue butterfly (Celastrina argiolus) pair mating, Hutchinson's Bank, New Addington, London, England, June.

Simon Colmer / Holly blue (Celastrina argiolus) Sussex, UK. June.