An insect’s body consists of three main parts: the head, thorax and abdomen
The vertex is the area above and between the eyes, the genae are the areas below and behind the eyes.
The thorax consists of three segments, the prothorax, the mesothorax and the metathorax – each of which carries a pair of legs. Wings are carried on the first two or, if only one pair of wings, on the middle one.
The abdomen has up to eleven segments. On the end of the abdomen their is often a pair of appendages called cerci. Some insects such as dragonflies use these to grasp the female while mating.
Some insects have a long needle-like ovipositor at the end of the abdomen. This is used for laying eggs in wood or even in other live insects!
Insects have one pair of compound eyes made up of lots of tiny lenses.
Many insects also have very simple eyes called ocelli. There are usually three ocelli on the top or front of the head.
All insects have one pair of antennae which are used to sense smell and touch
All insects have three pairs of legs. You can usually see four main parts: The coxa, which joins the leg to the thorax, the femur, usually the largest segment. Next the tibia, usually the longest segment. Finally the tarsus or foot which consists of one to five segments with one or two claws at the end.
Most insects have wings.
They usually have two pairs of wings. In those such as butterflies, moths and dragonflies both wings are membranous. In some insects such as grasshoppers, the front pair, called tegmina, are quite tough and protect the delicate hind wings. In beetles the front pair, known as elytra, are very hard and tough and make the insect look as though it has no wings.
The true flies have no hind wings, instead they have tiny pin-like structures which help to balance and stabilise the insect in flight.
© Dan Ambrose & Martin Rapley 2005