A firefly is a type of beetle.

萤一种甲。

Fireflies sparked in the darkness.

萤在黑暗中发光。

The firefly is a holometabolic insect, passing through the stages of being an egg, being a larva, molting, and pupation.

萤于「完全变态」的昆，一生历经卵、幼、蜕皮、化蛹及羽化的过程。