Insects are one of the largest groups of animals and belong to the phylum arthropoda which have a chitinous exoskeleton. In this group they are the largest one and characterised by having a body divided into three parts and three pairs of legs. Another feature is that most of their adults have wings. One problem in ordering them is their diversity:

• Primitive wingless insects and their allies
• Aquatic specialists
• Cockroaches, grasshoppers and their allies
• Lacewings and beetles
• Flies, moths and their allies
• Wasps, ants, bees