As Southern Damselfly "Coenagrion mercuriale" has not appeared on this thread yet, I thought I`d add it.
Southern is the smallest of the blue Damselflies.
It is found on small steams & flushes in southern England, south Wales & Anglesey.
The male has a "Mercury" mark on S2, and spear marks on S3 & S4.
The female,though a blue form exists, normally has an abdomen which is dull green below & mainly black above,with a Thistle shape on S2, there are blue divisions between the last few segments ( Distinct from Small Red "Melanogastrum" form which has red divisions.
Some amazing photo's and very knowledgeable people here. I am quite new to this, I got this shot of what I think is a Female emerald damselfly. Not seen one on here yet so thought I would post it. Neil.
For your consideration....my Dragonfly Pictures section was organized around this thread's Dragonfly Identification theme.
It focuses on North American dragonflies, and in most cases, species field identification tips are provided along with pictures of male and female specimens.
Dragonfly watching can be an enjoyable exercise in and of itself. Its utility expands when the fact that the presence of dragonflies in an area indicates good water quality, is taken into consideration.