There are four Neurothemis species that are quite similar and can easily be confused:
N. fluctuans, N. fulvia, N. terminata and N. ramburii. The differences are as follows:

The males (red body):
- N. fluctuans has the colouration on the underwing stopped at the pterostigma and then gradually curved back to the base of the wings.
- N. fulvia has the colouration on the underwing half way the pterostigma and then down curved back to the point of the wing (clear end of the wing is almost circularly shaped).
- N. terminata has the colouration on the underwing beyond the pterostigma and then in a rather straight line down to the edge of the wing.
- N. ramburii has the colouration on the underwing touching the pterostigma and then down, with a little angle, to the edge of the wing (1/3 of the edge of the wing is clear).

The females (yellow/brown body):
- N. fluctuans: only 1 type: clear wings; without any colouration to the wings.
- N. fulvia: only 1 type: with colouration in the wings, similar to the male.
- N. terminata: 2 types: a) with colouration in the wings, similar to the male; b) with clear wings and dark wing tips.
- N. ramburii: 2 types: a) with colouration in the wings, similar to the male; b) with clear wings and dark wing tips.

My photos show a young male N. fluctuans.

Ben Tre area, Mekong Delta, Vietnam, 23 December 2023