Two-tailed Spiders (Long-spinnered Bark Spiders) are a genus (Hersilia) of tree trunk spiders in the Hersiliidae family. They are known as Two-tailed spiders, because of their two enlarged spinnerets. They can't be found easily, because of their brown color that camouflage the tree bark very well. They have long striped and spiny legs. They live on a tree trunk and don't build web or shelter. They sit on tree trunk all the day and night waiting for their prey. Below are the pictures of a same spider taken with and without flash.
Two-tailed Spider Pictures