Not all spider bites are dangerous, since the majority of spider species are totally harmless for humans; with the exception of a few venomous ones, the rest are pretty safe. When a spider bites you, the first thing to do is trying to identify the species, if it be possible; knowing what type of spider bit you may be crucial in case an anti-venom has to be used. Spiders that live outdoors are more difficult to identify due to the large number of species both harmful and venomous. All in all, spider identification serves not only to the scientist but to the average person who either takes a great interest in the various spider species or who'd like to avoid risky exposures and eventual bites. Some varieties have golden hairs on their carapace that makes them look dusty and allows for a perfect camouflage. Trapdoor spiders may also have parallel bars on the abdomen, but this is not always the case, since diversity is at home even within the range of the same species. Trapdoor spiders are not that easy to identify since there are other similar species for which they are often mistaken: the funnel-web spiders and the mouse spiders are the most relevant examples here. The shape of the web woven by the hobo spider is truly unique, it consists of a very dense silk sheet which is usually curved upwards so that insects that come from above the structure may fall into it. The hobo spider waits in a tubular retreat until the prey is tangled in the threads and only then it comes out and injects the insect with the paralyzing venom. The special thing about these creatures is the way the females carry the egg sacs with them, and once the eggs hatch, the siblings remain attached to their mothers' back until they are large enough to detach and start a life on their own. Without being venomous, the wolf spider bite can cause a bit of trouble for more sensitive people. There are several other varieties related to the black widow spider; they live in South Africa and Australia, and the major difference from the North American black one is of color: they are red and brown. Even in North America there are three different types of the black widow spider and their classification is made according to the geographical area where they live: there is the northern black widow, the southern black widow and the western black widow; thus the species is widely spread from the south of Canada to Mexico.