On warm summer nights in many parts of Texas, tiny lights blink on and off above the grass. These lights come from fireflies, which some people call lightning bugs. Even though their names say fly and bug, fireflies are really a kind of beetle.

A firefly makes its light inside its own body. Special chemicals in the end of its belly mix with air, and the mixture glows. This kind of light is sometimes called cold light, because it gives off almost no heat. An old-fashioned light bulb, on the other hand, can get too hot to touch.

Fireflies use their flashes to send messages to each other. Each kind of firefly has its own pattern. Some flash quickly two or three times, and others glow for a long time. A firefly looking for a mate watches for the right pattern and flashes back.

Fireflies need dark, damp places with tall grass. Bright lights from houses and streets can make it hard for them to see each other’s signals. That is one reason some families turn off their porch lights on summer nights, so the fireflies can talk in the dark.