Dragonfly belongs to insect order Odonata and undergoes incomplete metamorphosis unlike other insects. True dragonflies belong to Anisoptera suborder.
The Larva: It is interesting to note that even though we’ve seen dragonflies mostly flying around us during hot summer months, they spend most of their life underwater as a larva. They can live underwater for as long as two years, and this is considered to be the longest stage in the life cycle of a dragonfly.
While the larva (nymph) stage can last as long as two years, the adult dragonfly lives for 6 months.