Widespread and common. Adults can be seen from May to the end of August. A common species, typically of lakes, especially deep open sites. Absent from small shallow pools such as those found on cutover bogs, though wandering adults will occur on these. It has been recorded at greater altitude than most other damselflies.

This species is similar to the Azure Damselfly, the Variable Damselfly and the Irish Damselfly but can be distinguished by the presence of a single stripe on the side of the thorax (visible in the photographs), the shape of the marking on segment 2 and by the shape of the pronotum.

KEY IDENTIFICATION FEATURES

• The bluest of the blue damselflies
• Males have a club-shaped black mark on second abdominal segment and the upper surface of segments 8 and 9 is all blue
• Broad antehumeral stripes
• The hind margin of the pronotum has a flat, shallow median lobe (see comparison of pronotums of blue damselflies)
• Females occur in three colour forms, typical, blue and brown
• Females have a medial spine on the underside of segment 8