|Length around 29-34mm; Wingspan
around 35-40mm; Hindwing around 14-21mm.
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. Segment eight (S8), however, is entirely pale blue.
Female Blue-tailed Damselflies come
in a variety of colour forms, with the colour darkening as the damselfly
ages. The thoracic markings and the tail spot are violet in the immature
form violacea, but salmon pink thorax and blue spot in the form "rufescens".
When mature the female may be blue (like the male) in the form "typica",
olive green thorax and brown spot in the form "infuscans" or pale brown
thorax and brown spot in the form "infuscans-obseleta". Male and female
both have bi-coloured pterostigma on the front wings.
Larvaes are aquatic, and prey on
small aquatic insects or other aquatic larvae. The adult damselflies prey
on small flying insects, caught using their legs like a basket to scoop
the prey up while flying, or insects taken from leaves.
At rest, the wings of most damselfly
species are held back together, unlike dragonflies, which rest with their
wings out flat.
Found in most types of water including
brackish or polluted water where it may be the only species present.