The male Rufous Marsh Glider (Rhodothemis rufa), also known as Spine-legged Redbolt, is a fairly large sized red dragonfly with a red thorax, red eyes and no black line or markings on its red abdomen.
Rhodothemis rufa has eyes bearly touching each other.
The similar looking male Scarlet Skimmer (Crocothemis servilia) has also red eyes but has a thin black line on the top of its abdomen and both eyes well touching each other.
Young males and females are brown with a mid-dorsal yellowish stripe on the thorax up to half way of the abdomen (see here).
Rhodothemis rufa has prominent robust spines on the legs.
It is widespread and fairly common in many Asian countries.

Chiang Mai area, Thailand, 24 December 2009