The insects of the world outnumber all other animal species by about four to one. North America has more than 100,000 kinds of insects. On average, a square mile of land is home to more insects than there are people in the world.
All insects have certain features in common. An insect's body has three parts: head, thorax, and abdomen. Most insects have a pair of antennae on the head and three pairs of jointed legs on the thorax. They also usually have two pairs of wings attached to the thorax.