Odonata is an order of insects, encompassing dragonflies (Anisoptera) and damselflies (Zygoptera). The word dragonfly is also sometimes used to refer to all Odonata. The term odonate has been coined to provide an English name for the group as a whole, but is not in common usage; most Odonata enthusiasts avoid ambiguity by using the term true dragonfly, or simply Anisoptera, when referring to just the Anisoptera.
A dragonfly is a type of insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera. It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body. Dragonflies are similar to damselflies, but the adults can be differentiated by the fact that the wings of most dragonflies are held away from, and perpendicular to, the body when at rest.
Damselflies (suborder Zygoptera) are insects in the order Odonata. Damselflies are similar to dragonflies, but the adults can be differentiated by the fact that the wings of most damselflies are held along, and parallel to, the body when at rest. Furthermore, the hindwing of the damselfly is essentially similar to the forewing, while the hindwing of the dragonfly broadens near the base, caudal to the connecting point at the body.
The Epiprocta Lohmann, 1996 is one of the two extant suborders of the Odonata. It is a relatively recently-proposed suborder, having been created to accommodate the inclusion of the Anisozygoptera. The latter has been shown to be not a natural suborder but rather a paraphyletic collection of lineages (Lohman 1996, Rehn 2003), so it has been combined with the previous suborder Anisoptera, the well-known dragonflies, into the Epiprocta.
The obelisk posture is a handstand-like position that some dragonflies and damselflies assume to prevent overheating on sunny days. The abdomen is raised until its tip points at the sun, minimizing the surface area exposed to solar radiation. When the sun is close to directly overhead, the vertical alignment of the insect's body suggests an obelisk.