Britain's bulkiest Dragonfly. Its bright colours and active habit make it very obvious when hunting over medium to large water bodies. It rarely settles, even eating its prey in flight. Both sexes have a bright, apple-green thorax and green or blue eyes. The costa is bright yellow. They often fly with the rear of the abdomen bent slightly downwards.
The male has a sky blue abdomen with a central dark line.
The female has a green abdomen, similarly marked, which may become blue in warm weather.
Mostly associated with large, well vegetated ponds and lakes, but may be found over canals and slow moving rivers. The female lays her eggs, alone, in floating pondweed.