Male and female are variable in color and pattern. The male has translucent wings which each have a broad, dark iridescent blue-black spot (or band) across the outer part. On immature dragonflies the spot is dark brown. The body can be a metallic blue or bluish green or a combination of both colours, depending on the time of year and location.

Female banded agrion (Calopteryx splendens)

Female banded agrion (Calopteryx splendens)