Complex sentence: The trapdoor is hinged on one side with silk and the spiders, which are usually nocturnal, typically wait for prey while holding onto the underside of the door with the claws on their tarsi.
Split into simpler sentences: The trapdoor is hinged on one side with silk. The spiders, which are usually nocturnal, typically wait for prey while holding onto the underside of the door with the claws on their tarsi.