Male. Taken at Otmoor, Oxon on April 30th 2011. Click image for larger version.
(1/320th sec at F11. Approx 1.6x life size.)
Male. Taken at Otmoor, Oxon on April 30th 2011. Click image for larger version.
(1/400th sec at F11. Approx 1.6x life size.)
Female. Taken at Otmoor, Oxon on May 20th 2007. Click image for larger version.
(Approx 1.6x life size.)
Male of form praenubila. Taken at Otmoor, Oxon on June 13th 2010.
(1/640th sec at F11. Approx 2x life size.)

© David Hastings

Description

Wingspan: 64 - 80 mm; body length: 40 - 48 mm
 
The sexes are alike, with a brown abdomen becoming darker towards the rear, a brown thorax and brown eyes. The is a row of yellow spots along each side of the abdomen. The most noticeable feature is the colouring of the wings. The nodus (half-way along the leading edge of each wing) has a very dark spot, which gives the insect its name. The wing bases are also dark. A colour form "praenubila" has a general darkening of the wing tips.
 
This species prefers still water, preferably with well-developed vegetation. Males are aggressively territorial, taking up positions on bankside or emergent vegetation, from which they launch missions to chase intruders or intercept a female. Mating occurs in flight, and is very brief. Eggs are laid in flight. They hatch after about four weeks and the larvae live in decaying plant debris. Nymphs take at least two years to mature into adults.
 
The flight time is late May to July. But emergence started in late April in 2011.

Sightings

25-May-2011	:	Cherwell flood plain, Oxford (1)
21-May-2011	:	Bentley Wood, Wilts (1)
15-May-2011	:	Parsonage Moor, Oxon (1)
30-Apr-2011	:	Otmoor, Oxon (8)
11-Jul-2010	:	Otmoor, Oxon
24 to 29-Jun-2010	:	The Brenne and Vienne, France
22-Jun-2010	:	Bullfield Lake, Oxon
13-Jun-2010	:	Otmoor, Oxon
06-Jun-2010	:	Thames at Pinkhill, Oxon
21-May-2010	:	Otmoor, Oxon
05-Jul-2009	:	Otmoor, Oxon
31-May-2009	:	Otmoor, Oxon