Flight period: June to September (occasionally May)
The abdomen appears quite slim and has a pronounced dorsal keel. The wings have a straw yellow costa and yellow or brown pterostigma. At rest, the wings are often held well forward. The thorax has pale yellow ante-humeral stripes which fade with age in the male.
Male: develops a blue pruinescence over the whole length of the abdomen. Its eyes are blue-grey.
Female: has a pale, yellowish-brown abdomen with a medial black line.