Lethocerus deyrollei is a species of giant water bug (family Belostomatidae) that traditionally is included in the genus
Lethocerus, although recent authorities places it in the
Kirkaldyia. They are large (4.8–6.5 cm or 1.9–2.6 in long), predatory and nocturnal insects. They are one of the best known giant water bugs and are found in Japan, Korea, east China, east Indochina and the Amur region of Russia. They are very common in much of their range, but have declined...
(Wikipedia)