At rest, Emerald Damselflies all spread their wings at an angle to the body, unlike other damselflies.
The Small Spreadwing can be distinguised from the other Emerald Damselflies (Lestes species) by looking at the back of the eyes (head): the top half of the back is dark and the bottom half is yellow.
From the other 5 Emerald Damselflies in The Netherlands only the Southern Emerald Damselfly (Lestes barbarus) shows this feature but this species has two coloured (brown and cream-coloured) pterostigma (wingspots).
In addition, adults Small Spreadwings can be distinguished from the other Lestes species by their light brown pterostigma with clear light borders.
Adult males show blue at the end of their bodies (S9 and S10) but not at the base (S1 and S2) as in the Common Emerald Damselfly (Lestes sponsa) and Emerald Spreadwing (Lestes dryas).
And finally, a very good way to distinguish the Small Spreadwing from the Common Emerald Damselfly (especially in females) is to look at the side of the first segment of the abdomen (S1). The Small Spreadwing shows here a small dark spot (in Dutch: the "Neijtsvlek") whereas the Common Emerald Damselfly doesn't.
Top & Left: Dwingelderveld National Park, The Netherlands, 24 July 2012
Middle: De Mosbulten, Son en Breugel, The Netherlands, 17 July 2018