A tandem (mating) pair of Common Blue Damselflies © Mark Tyrell
Common Blue Damselfly Female © David Kitching - showing lack of coenagrion spur, thistle mark on segment 2 (side view) and dull colour form (green form also exists)
Common Blue Damselfly Male © David Kitching - showing the stalked ball on segment 2 and the lack of a coenagrion spur
Click on images to enlarge
In many ways this could be considered to be the most typical British damselfly. It shares its blue and black colouration with several other species. It can be distinguished from the others by its broad ante-humeral stripes. In the male, S2 has a characteristic mark of a spot linked to the inter segment suture by a short line. S8 and S9 are entirely blue.
The female occurs in two colour forms, one blue, as in the male, the other dull green. The mark on S2 is thistle shaped and there is a "Christmas tree" shaped stepped triangle on S8.
They often perch gregariously on emergent plant stems, all facing the same way.
Flight Period: April - September (October)
No spotting on the back of the head. Three distinctive thin horizontal stripes on caudal lamellae (sometimes very faint)
It occurs in most waters and on large lakes is usually the most abundant species.
Status & Distribution
Abundant throughout the British Isles.
This species is easily confused with the various members of the genus Coenagrion. Look at S2 (on the males) for distinguishing characters. It does appear particularly blue compared with other similar species. The females can be particularly tricky to distinguish apart.