The suborder Anisoptera is roughly equal to the common name 'dragonfly'. The family Aeshnidae is a family of dragonflies that can be found on nearly every continent on Earth, and are perhaps most notable because they include most of the larger specimens of dragonfly, which are often commonly called hawkers (UK) or darners (US).
Aeshnidae have partially fused eyes, meeting at the top of their head. The other defining characteristics of the family are less obvious: the females have an ovipositor, and the anal triangle at the base of the hind wing is two-three cells wide. The larvae are generally slender compared to those of other families, with long and flat extensible lower lip, six or seven segments in their bristlelike antennae, a median cleft in their ligula (forehead), and their prementum widens toward the distal half. Given that there are over 50 different genera, there are few firm and easy rules for easily determining if a given dragonfly is a member of Aeshnidae, but the odds are if you see a large dragonfly, it is an Aeshnidae.
The American name 'darner' comes from the resemblance of their abdomens to darning needles, and they are sometimes called "the devil's darning needle", and are said to sew up the lips of young children who lie. This myth may be related to the females piercing plant stems with their ovipositors when they lay eggs. The label 'hawker' may refer to their ability to hover and dart like hawks, along with their hunting ability.
The name Aeshnidea may be the result of a printer's error in spelling the Greek Aechma, meaning 'spear'. In the past the spelling 'Aeschnidae' was often used, but is no longer; the 'sch' spelling is still found in many derived genus names such as Rhionaeschna and Acanthaeschna, with the spelling in which they were originally cited.