Banded demoiselle (Calopteryx splendens) 2011-07-23 the male is blue with dark spots - the female is green without spots. Not the sharpest picture, but it shows both together. These dragonflies accompanied us all along the canals in England during this trip. For a sharper shot of just the male: http://www.jerrybarton.eu/gallery/8068199_FK3HC#1395469728_fBtNLvP