Hersiliidae is a tropical and subtropical family of spiders first described by Tamerlan Thorell in 1870, which are commonly known as tree trunk spiders. They have two prominent spinnerets that are almost as long as their abdomen, earning them another nickname, the "two-tailed spiders". They range in size from 10 to 18 mm (0.4 to 0.7 in) long. Rather than using a web that captures prey directly, they lay a light coating of threads over an area of tree bark and wait for an insect to stray onto the patch. When this happens, they encircle their spinnerets around their prey while casting silk on it. When the insect is immobilized, they can bite it through the shroud.

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