Dragonflies are the fastest flying insects. They swoop over the streams and ponds up to 90 kilometers per hour. Meanwhile, damselflies have longer, thinner bodies and are more delicate, with a slow, flattering flight. The wings of the damselfly are almost transparent. They shimmer as the damselfly searches for small insects to eat.

Dragonflies and damselflies live near water. They lay their eggs on plants. When they hatch, the young ones, called nymphs come out of the eggs. They feed on
water creatures, and after two years the nymphs grow into adults.

What is the main idea of the second paragraph?