If you don’t look very closely, you might confuse these spiders with another group of animals often called “daddy long-legs” or “granddaddy long-legs,” the harvestmen (order Opiliones). We are happy to help dispel a pernicious myth: many people repeat the claim that these are the most venomous spiders in the world, but that their fangs are too small to bite humans. However, these spiders are not at all aggressive and bites are exceedingly rare and produce nothing more than a short-lived stinging sensation. These spiders, also like most others, do have fangs and in large individuals these are technically capable of piercing human skin. The venom of these spiders is no more toxic than that of an average spider (almost all spiders have venom glands!). How many spiderlings do you count? How many legs do they have? If you’re lucky enough to see a spider with an egg sac in your own house, keep watching it every day–very soon those eggs will hatch! Look at the tiny spiderlings (baby spiders) that result. Chelicerae are special types of jaws that spiders and their relatives have, which are normally used for feeding (each chelicera is tipped with a fang), but in this case the female is using these structures for a different purpose: holding on to her young. You can easily see the individual eggs when you look closely-count how many you see! Also, while you are up close, notice how the egg sac is being held by the mother spider: she carries it using her chelicerae (singular: chelicera ). This is not part of the body, but is an egg sac, a group of eggs that (in this species) the female lays and loosely binds with silk.

Occasionally you might notice something that appears to be a third, spherical body segment that has grown underneath the spider.

We know that many species that are close relatives of these spiders are found in caves and hollow trees in the wild, but there are a few, including Pholcus phalangioides, that we only find living in man-made structures.

Spiders that look just like this are found in buildings nearly everywhere in the world, and evidence about their distribution suggests that they were introduced from southern Europe to the rest of the world accidentally by the activities of human beings. The whole body, when fully grown and not including the legs, is about 1 cm long. How do you know the species in your house is this species?ġ) the extremely long legs, several times longer than the bodyĢ) the abdomen (the hind part of the body, with no legs) is shaped like a long oval, not a sphereģ) the cephalothorax ( cephalo = head thorax = breastplate), the front part of the body with the legs, is light-colored, but has a dark oval or triangle marking in the middle of the back which is not distinctly divided into two halves.

Long body cellar spider facts