Identifying Blue Damselflies

Predominantly blue damselflies can be tricky to identify.. There are three main species that cause confusion, the Common Blue, Azure and Variable. In males the best feature to distinguise them is the shape of the black pattern on the second segment of the body.

In the common blue this is a circle rising on a short stem, on the Azure a U shape mark, and on the variable the U has a stem.

The top of the thorax also differs: The common blue has much wider ante-humeral stripes than the Azure, while the variable frequently has broken or incomplete stripes.

You can also see, in the above photos of the azure and variable, the "coenagrion spur", the small black line jutting forwards on the side of the thorax, below the ante-humeral stripes. This is present on all British species of coenagrions, but not on the common blue.