钉螺Oncomelania hupensis是血吸虫的中间宿主。近年来,我们在室内饲养钉螺的过程中,发现毛蠓Psychoda alternata Say幼虫寄生于钉螺体内,使之死亡。一钉螺内可有多条毛蠓幼虫,甚至达23条之多。毛蠓幼虫在水中游动或在潮湿地方爬动,遇到钉螺时,即附于其上取食软体组织,并进入螺壳内。幼虫可横穿钉螺软体的各个部位。钉螺致死后毛蠓幼虫仍可继续生长或爬出再进入其它钉螺内。 Oncomelania hupensis is an intermediate host for schistosomiasis. In recent years, we indwelling snails indoors and found that the Psychoda alternata Say larvae parasitize snails and kill them. A snail can have more hairy larvae, even up to 23 as many. Maucus larvae swim in the water or crawl in wet places, encountered snails, that is attached to its feeding on the soft tissue, and into the shell. Larvae can cross the snail soft body in all parts. After the snail dies, the hairy larvae can continue to grow or climb out into other snails.