An insect body has many component parts and those parts have somewhat complex technical names, compared to plain English, that is. Some of the terminology involved is frequently used to describe so-called diagnostic features so a passing familiarity with the more frequently used terms can be a distinct advantage.
Bodies
Some identifying features revolve around parts of the insect body itself. Being closely related insects, many of these terms are shared between dragonflies and damselflies – the overall body plan is essentially the same.
Here are some basic terms presented on a dragonfly body plan.
Many damselfly terms are shared with dragonflies but a couple of terms occur in damselfly anatomy that do not feature strongly in dragonfly anatomy, notably pronotum and post-ocular spot. Some terms are encountered only in certain species which possess a specific feature, too. Such is the case with vulvar spine.
Here is an annotated general damselfly body plan.
Wings
The intricacies of dragonfly wing venation are key to determining genus and minor differences can help separate species within genus. Classically here we have the Rspl and arculus in Orthetrum coerulescens vs. O. brunneum, and a yellow costa in Aeshna juncea.
Here is an annotated dragonfly wing venation diagram.
Damselfly wing venation doesn’t seem anywhere near as important when it comes to identification as those of a dragonflies but, just for the sake of completeness:
Here is an annotated damselfly wing venation diagram.