moth fly; drain fly; sand fly
Refers to small, fuzzy flies of the family Psychodidae, often found in bathrooms or drains. The term covers various species known as moth flies, drain flies, or sand flies in English.
Moth flies appeared in the bathroom.
排水口からチョウバエがわくのを防ぐ方法を調べた。
I looked up ways to prevent drain flies from breeding from the drain.
Compound of 蝶 (chō, 'butterfly') and 蝿 (hae, 'fly'), referring to its moth-like appearance. The exact historical derivation is uncertain.