Banded demoiselle (Calopteryx Splendens). A brightly coloured and large damselfly with males a metallic blue with a dark blue band on the wing. Females are a metallic green. Adults prey on small insects on the wing and the flight period is between April and early October. They are normally associated with slow moving streams and rivers. It is found across Europe, as far east as northern China. Photographed in Somerset, UK, in May.