(from the wiki page)
As a seasonal symbol in Japan, the dragonfly is associated with autumn. More generally, dragonflies are symbols of courage, strength, and happiness, and they often appear in art and literature, especially haiku.
In Europe, dragonflies have often been seen as sinister. Some English vernacular names, such as “horse-stinger”,”devil’s darning needle”, and “ear cutter”, link them with evil or injury. Swedish folklore holds that the devil uses dragonflies to weigh people’s souls.
Japanese children catch large dragonflies as a game, using a hair with a small pebble tied to each end, which they throw into the air. The dragonfly mistakes the pebbles for prey, gets tangled in the hair, and is dragged to the ground by the weight.