noun
Refers to a type of fungus gnat (family Mycetophilidae) whose larvae are bioluminescent, often found in caves or damp forests. The English term 'glowworm' can also refer to other luminous insects, so context may be needed.
洞窟の中でヒカリキノコバエの幼虫が青白く光っていた。
Inside the cave, the larvae of the glowworm were glowing pale blue.
蛍 (firefly) is a beetle that flies and emits light as an adult, while ヒカリキノコバエ is a gnat whose larvae glow.
Compound of 光 (ひかり, 'light') + キノコバエ (fungus gnat). The name describes the bioluminescent larvae of this gnat.