Dragonflies and damselflies belong to the insect order Odonata meaning ‘toothed jaws.’ They are so named due to the tooth-like ridges present on the jaws, though this also happens to be a very fitting name as they are voracious predators both as larvae and adults. These remarkable insects originated some 300 million years ago and have survived with relatively little change in their basic structure. Collectively known as Dragonflies they are divided into two distinct sub-orders, the Anisoptera (true dragonflies) and Zygoptera (damselflies). There are a number of differences between these sub-orders which will help you decide if you are looking at a dragonfly or damselfly:

Anisoptera (Dragonflies)

Zygoptera (Damselflies)

Scarce Chaser
Female Scarce Chaser  Photograph ©  M. Randall
Blue-tailed Damselfly
Male Blue-tailed Damselfly  Photograph ©  M. Randall

Anisoptera means ‘unequal wings’ and they are so named as the forewing is narrower than the hindwing. They are generally larger and more robust with a powerful flight. When the insect comes to rest it leaves the wings outstretched. The head shape is spherical with eyes that cover most of the head and usually meet in the middle at a contact point. These features are illustrated by this aptly named female Scarce Chaser only ever recorded once in Shropshire. Click on the photo to take a closer look.

Zygoptera means ‘equal wings’ as the wings do not differ in shape. The damselflies are usually smaller insects with a weaker fluttery flight and when they come to rest most species fold the wings neatly together and hold them above the abdomen. They have a rectangular head shape with eyes located at the side of the head which are clearly separated with no contact point. This Blue-tailed Damselfly  illustrates a number of these features. Click on the photo to take a closer look.