These are pictures of Daddy Long Legs, commonly mistaken for Daddy Long Leg Spiders. They are not spiders, in fact, but are in the same class (Arachnids). They do not spin webs and are venomless.
In North America, two arthropods go by the name of Daddy Long Legs. There is the spider, Pholcus phalangioides, also known as the cellar spider because where they can be found in basements and wine cellars. However, in this case, these photographs are of another order of arthropod called Daddy Long Legs as well.
Belonging to the order Opiliones, (spiders are in the order Araneae) these Daddy Long Legs, aka Harvestmen, have a great deal in common with spiders. For example, they have eight legs and their mandibles resemble that of spiders. However, its abdomen and thorax are fused appearing as an oval. They also are venom less and do not have silk glands.
Harvestmen where named by farmers who saw the arthropods out in the fields during the fall, a time when they lay their eggs. They are prolific in all habitats around the United States and Canada, except for the deserts of North America. In the north, they die off by winter, but in the south, they tend to hide out in organic matter such as tree stumps and dead leaves and wait out the colder months.
Daddy Long Legs are omnivores, though some species are exclusively predators. They are nocturnal foragers, and begin to seek out food during twilight. They feed upon live insects, dead animals, and plants.
As stated above, Daddy Long Legs are not venomous. On the other hand, the Daddy Long Leg Spiders do have venom, but it is not potent enough to cause injury to human beings.