As strange as it sounds, the Pholcidae, or Cellar Spider is one of the most misunderstood spiders in the world. There are three different critters commonly referred to as the Cellar Spider:

The Crane Fly (which looks like a giant mosquito), the Harvestman (which is commonly mistaken for a spider but has only one body part and no fangs), and then there is the actual Cellar Spider. However, it has become so common for each of these to be called Cellar Spiders, or Daddy Long-Legs, that it is now considered correct for all three.
Pholcidae is actually not a species but a family of spiders. There are nearly 2,000 species of Pholcidae distributed in the entire USA and also worldwide.
There is a common myth about Pholcidae. It says that it is the most venomous spider in the world, but its fangs cannot penetrate human skin. This is far from true. In fact, they can bite, but they are completely harmless.
Pholcidae Description
The Cellar Spider has a small thin body with very long thin legs. It is usually a tan or gray shade of color.

Size
The body will reach a maximum length of up to 10 mm (less than half an inch) and its legs may grow to around two inches long (51 mm).
Web
Fitting to this spider, their webbing is made of very thin strands and strung about haphazardly giving it the look of a light cobweb. The Daddy Long-Leg Spider often builds its web in the corners of the ceiling, behind bookshelves, under and behind couches, between joists in the basement, etc…
Bites
It is difficult to get bitten by a Cellar Spider, and on the very rare occasion one does bite, it is completely harmless to humans. At the worst, it may leave a small red blemish that will fade fairly quickly.
Side Fact
Pholcidae is one of the best spiders to have around, especially, if you live in a state, with more poisonous spiders. They are known to actually hunt down and kill the more dangerous spiders to humans. When the Cellar Spider is in its web and feels threatened, it has the ability to vibrate itself within the web to make it less visible.
Pholcidae Scientific Classification
- Kingdom: Animalia
- Phylum: Arthropoda
- Subphylum: Chelicerata
- Class: Arachnida
- Order: Araneae
- Infraorder: Araneomorphae
- Family: Pholcidae
Common Names
Cellar spider, daddy long-legs spider, granddaddy long-legs, carpenter spider, house spider, daddy long-legger, skull spider, vibrating spider
US states where the cellar spider is found

Every US state – Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming