Ischnura elegans (Blue-tailed Damselfly)

Blue-tailed damselfly, common bluetail

Common across its range from Western Europe (save for Portugal) to Eastern Asia

Medium sized damselfly. 

Male patterned blue and black on head and thorax. Abdomen dark from above and pale ventrally, with only segment 8 being completely blue. 

Female comes in various colour morphs, including salmon pink, violet and pale green when immature, as well as blue, olive green and pale brown morphs when mature.