Dragonflies and damselflies are part of the order Odonata (odonates). Insects of the order Odonata are divided in two suborders: Epiprocta (dragonflies) and Zygoptera (damselflies).
Dragonflies
Epiprocta are commonly referred to as dragonflies. Most species of the suborder Epiprocta belong to the infraorder Anisoptera, which includes the darners, clubtails, spiketails, and skimmers. Anisoptera are characterized by the following:
- The wings at rest are held perpendicular to the body
- The hindwings broaden at the base
- The eyes come close to or touch each other at the top of the head
Damselflies
Zygoptera are commonly referred to as damselflies. These include the broad-winged damsels, spreadwings, pond damsels, and shadowdamsels. They can generally be recognized by the following:
- The wings at rest are held parallel to the body (except in spreadwings)
- The fore- and hindwings are similar
- The eyes are separated
Zygoptera are often smaller and have a weaker flight than Anisoptera.
Identification and Coloration
Within each suborder of odonates, identification often relies on examination of the coloration of various body parts. As illustrated by photos on this site, coloration within a species can, however, vary considerably. Factors influencing coloration include age, sex, reproductive status, and temperature.
In addition, mature females of some damselfly species come in two forms: an andromorph (male-like) and a less colorful heteromorph forms. Consequently identification, particularly of damselflies, cannot in many cases rely exclusively on coloration, but requires examination also of structural features, such as the shape and size of terminal appendages.