glowworm

2. The wingless female of certain beetles that emits a greenish light to attract mates.

The glowworm waited in the grass, glowing softly to attract a mate.

3. The larva of a fungus gnat that spins sticky glowing threads to catch small insects.

In the cave, glowworm larvae hung glowing threads to trap tiny flies.

4. Any of various luminous insects or worms, especially in folklore and old stories.

The old tale said a glowworm could light a traveler's path through the woods.