hister beetle; clown beetle
Refers specifically to Hister jekeli, a type of hister beetle. The name エンマムシ (閻魔虫) comes from its defensive behavior of tucking in its legs and playing dead, reminiscent of Enma, the judge of the dead.
The hister beetle tucks in its legs when it plays dead.
Katakana spelling is standard for this insect name; usually written in kana.
Kanji spelling exists but is rarely used; the insect is almost always written in kana.
From 閻魔 (Enma, the Buddhist judge of the dead) + 虫 (mushi, insect), referring to the beetle's habit of playing dead with legs drawn in, resembling a corpse before judgment.