Coenagrion

Coenagrion is a genus of damselflies in the family Coenagrionidae, commonly called the Eurasian Bluets (although three species are found in North America). Species of Coenagrion are generally medium-sized, brightly coloured damselflies.

Identification

Males are small blue damselflies with black markings. The blue areas may be partly greenish or whitish. Females have more extensive black markings, and are more often green or brownish. A damselfly with plain pterostigmas, with roundish postocular spots, with antehumeral stripes narrower than the black line below it, and with two short black lines on the thorax sides, will in most cases belong to Coenagrion.

Separation from other genera

Enallagma normally have antehumeral stripes wider than the black line below them and just one short black line on the thorax side. Ischnura males have bi-coloured pterostigma. Enallagma and Ischnura females have a vulvar spine. Erythromma species are darker, with reduced or no postocular spots, and males have red or all-blue eyes, whereas eyes of Coenagrion are blue with dark caps. The blue Erythromma lindenii is very similar, but differs in many details, like wider antehumeral stripes, an all-black upperside to S2 and a shorter 'tail-light' positioned further at the tip of the abdomen.

Behaviour

Males typically fly low among or along riparian vegetation. They rarely venture far from water. MAles and females in tandems often oviposit in concentrations on floating vegetation. The male often holds a conspicuous upright posture when in tandem with the female.