SPT

small pincertail

green-eyed hooktail

onychogomphus forcipatus

small pincertail

small pincertail — Male. Although eye colour is often used to distinguish small pincertail from large, it is not completely reliable.
In general, if the eyes are green without any hint of blue then it is most probably a small pincertail. If the eyes are blue or have blue tints it could be either species, although it is most likely to be a large pincertail.

small pincertail — Male. Although eye colour is often used to distinguish small pincertail from large, it is not completely reliable.
In general, if the eyes are green without any hint of blue then it is most probably a small pincertail. If the eyes are blue or have blue tints it could be either species, although it is most likely to be a large pincertail.

small pincertail — Male. Most text books seem to regard appendages as a key identifier. Personally I do not find it easy to get photos with these in the desired orientation to get a definitive answer. However, it appears that dark appendages can occur with small pincertails but not with large (see below for an example).
Fortunately there are several other diagnostics that can be used, namely the number of cells in the anal triangle, the colour of the forehead and whether the yellow collar is broken or not.

small pincertail — Male. Most text books seem to regard appendages as a key identifier. Personally I do not find it easy to get photos with these in the desired orientation to get a definitive answer. However, it appears that dark appendages can occur with small pincertails but not with large (see below for an example).
Fortunately there are several other diagnostics that can be used, namely the number of cells in the anal triangle, the colour of the forehead and whether the yellow collar is broken or not.

small pincertail — Male. This picture hopefully shows all the features mentioned above, confirming small pincertail. In summary: green eyes, dark appendages (in this case, but not always), 3 cells in anal triangle, unbroken yellow collar and forehead showing yellow.
I'm disappointed to not yet have a photo of a female but the appendages are quite different from the male, making a diagnosis easier.
It should also be noted (see large pincertail for further comment) that the eyes are separated.

small pincertail — male

small pincertail — male

small pincertail — Male in obelisk position with good view of pincers. In the south (here Lozere, France) eyes can be bluish. Yellow bar on forehead is visible.