From Ring of Brodgar
Vital statistics
This data is specified at the individual Terrain pages.
Bog, Fen, Swamp

How to Acquire

Dragonflies only fly around in swamps!, so you can't run after them, which makes them quite tricky to catch. The easiest way currently is to catch them on horseback, as horses currently move normal speed in a swamp. An alternative method (if you're good at it) is to try and intercept them since their flying pattern is quite clear. Another way is just to right-click and wait, it might take a while but sooner or later you will catch it.

When caught the dragonfly will usually be a Emerald Dragonfly. But sometimes you may and up with the very rare but superior Ruby Dragonfly instead.

Emerald- versus Ruby-Dragonfly Curiosity data

Emerald Dragonfly8003.6332
Ruby Dragonfly240044

(More curiosity data available at Curiosity Tables)