Adult insects can be recognized from their six legs. Insects also usually have large eyes. 

The abdomen of the insect usually contain two pairs of wings, which make it possible for the insect to fly. Often, only one of the two wing pairs is actually used to fly, whereas the other pair of wings is used to protect the flying wings. 

Many insects undergo a complete metamorphosis. The insect egg hatches into an insect larva, which usually eats plant parts. In time, the larva grows and finally pupates. The pupa hatches into an adult insect, such as a butterfly. 

Insects can be either herbivores or predators.

The complete metamoprhosis of a swallowtail butterfly: the egg hatches into a larva, the larva grows into a pupa, and the pupa hatches into an adult butterfly.