The story
Both phorid flies are called "coffin flies" because they can be found in coffins, being able to detect buried corpses and crawl through soil to reach them.
Etymology from Wiktionary, CC BY-SA 4.0.
coffin fly
Today it means: The scuttle fly, Megaselia scalaris, an omnivorous fly which eeds on plants (nectar) as well as carrion. Full definition →