A group of daddy long-legs of the order Opiliones. A widespread myth holds that daddy longlegs, also known as granddaddy longlegs or harvestmen, are the most venomous spiders in the world. We’re only safe from their bite, we are told, because their fangs are too small and weak to break through human skin.
The Manila hemp is derived from a species of banana originally from the Philippines, whose fibers are tough. The hemp is then used during the paper making process, similar to how Kraft paper uses wood pulp. So the mystery is solved, the manila envelope gets its name from the hemp in which it is made from.