noun
water scorpion; water stick insect
Refers specifically to the species Ranatra chinensis, an aquatic insect resembling a stick. Common name in Japanese.
池でミズカマキリを見つけた。
I found a water scorpion in the pond.
ミズカマキリは細長い体をしている。
The water scorpion has a long, slender body.
Compound of 水 (mizu, 'water') and カマキリ (kamakiri, 'mantis'), referring to its mantis-like appearance and aquatic habitat. The kanji 蟷螂 is a rare Chinese-derived spelling for mantis.