The Scarce Blue-tailed Damselfly or Small Bluetail, Ischnura pumilio, is a member of the damselfly

Damselfly

Damselflies are insects in the order Odonata. Damselflies are similar to dragonflies, but the adults can be distinguished by the fact that the wings of most damselflies are held along, and parallel to, the body when at rest...

 family Coenagrionidae

Coenagrionidae

The insect family Coenagrionidae is found in the order Odonata and the suborder Zygoptera. The Zygoptera are the damselflies, which although less known than the dragonflies, are no less common. There are more than 1100 species in this family, making it the largest damselfly family...

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The typical male has a black abdomen

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

 with a bright blue spot on tail (segments 8 and 9). It is very similar to the Blue-tailed Damselfly

Blue-tailed Damselfly

The Blue-tailed Damselfly, Ischnura elegans, is a European damselfly.Adult male Blue-tailed Damselflies have a head and thorax patterned with blue and black. They have a largely black abdomen with very narrow pale markings where each segment joins the next...

, Ischnura elegans but on that species the blue spot is mostly on segment 8. Females undergo a change of colour as they mature. The immature female is bright orange, the aurantiaca phase, but matures to a greenish-brown.