Emperor Dragonfly – Anax imperator

European common name: Blue Emperor

The Emperor Dragonfly – Anax imperator, is a common and easy to spot dragonfly owing to its tireless flight, size and colouring.



The region’s largest dragonfly. Inflight photos in particular show just how big and powerful the abdomen is; Emperors are easy to identify even from a distance. A tireless flier high over the water and along the water’s edge, they are very territorial, and will chase off other Odonata.

Males are striking, the thorax and first segment of the abdomen is apple green, the remainder of the abdomen is a vibrant blue, with discontinuous dark brown or black lateral markings, and a continuous dorsal stripe. The eyes appear blue from above and green below. The frons is noticeably yellow, making the male Emperor a very colourful dragonfly.

The female abdomen has brown markings similar in pattern to the male, but broader. Females have two colour forms, green and blue. The green form thorax and abdomen is green, but not as intense as the apple green of the male. The blue form female is blue green, resembling the male but without the same intensity of colour.

Colours of dragonflies may become more subdued at lower temperatures, and this can lead to some variation in the appearance of Emperors.

Overall length: 66 – 84 mm
Wings: 45 – 51 mm

Its size, and the mainly blue (male) or green (female) abdomen and green thorax, make it easy to separate from the other Hawker dragonflies that are common in Bedfordshire.

The Lesser Emperor – Anax parthenope is similar in appearance but with a brown thorax. It is extending its range but is only a rare visitor to the area.

Lakes, large ponds, and slow rivers with lots of vegetation.

Common throughout the county at still water sites like Felmersham NR, Marston Thrift,  Marston Vale CP, Priory CP, and also often encountered along the River Great Ouse and River Ivel.

Visible from late May to early September, peaking in June and July.

Emperor Dragonfly - Anax imperator Male, Marston Thrift.
Male Emperor Dragonfly – Anax imperator
Emperor Dragonfly - Anax imperator Female ovipositing at Marston Thrift.
Female Emperor Dragonfly – Anax imperator

External links for Emperor Dragonfly – Anax imperator:
British Dragonfly Society | Wikipedia