They all have:
1) three body parts – a head, thorax and abdomen
2) a pair of antennae
3) two pairs of wings
4) three pairs of legs
They often have large, compound eyes.
There are so many species of insects that scientists believe they make up most of the species on Earth.
Insects grow up in one of two ways. Some undergo incomplete metamorphosis. This is when young hatch and look like miniature adults, called nymphs. As they grow, they shed their hard outer layer – their exoskeleton. Each new size is called an instar. Insects like grasshoppers grow this way.
Most insects, however, go through a complete metamorphosis. This is when the new hatchlings, called larvae, look completely different from the adults. They feed until they reach a certain size and then form a protective cocoon or chrysalis and pupate. During pupation their body breaks down and changes into the adult form. Insects like moths and butterflies grow this way.
Though many insects are pests, they also play important roles we cannot live without like pollinating our plants, decomposing waste, and producing things like honey and silk.
For more about Insects, go to: All About Insects.
Orders: Coleoptera (beetles), Hymenoptera (bees), Lepidoptera (butterflies), (Odonata) dragonflies, and many more orders.