The aquatic larvae of the family Hydrochidae (Coleoptera) have been considered ‘mystery larvae’, because ecological knowledge about them is lacking. We discovered that Hydrochidae larvae (Hydrochus japonicus Sharp) are benthic via laboratory rearing. The larvae have a terminal spiracular atrium, but we did not observe them breathing at the water surface. The larvae fed on Naididae worms that were collected from the same habitat.

中文翻译：

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Hydrochus japonicus（鞘翅目：Hydrochidae）的实验室饲养表明幼虫生活在水底

Hydrochidae (鞘翅目) 的水生幼虫被认为是“神秘幼虫”，因为缺乏关于它们的生态学知识。我们通过实验室饲养发现水螅科幼虫（Hydrochus japonicus Sharp）是底栖动物。幼虫有一个末端气门心房，但我们没有观察到它们在水面呼吸。幼虫以从同一栖息地收集的 Naididae 蠕虫为食。