Experts in the field often say that spider identification is tricky since very many species resemble each other, and the venomous and the non-venomous ones are found in a complex who's who relationship. Presently, there are all sorts of devices that allow people to catch and analyze the spiders that live in their homes so as to find out whether they are poisonous or not. 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. It is not unusual to misdiagnose various skin infections as brown recluse spider bites, since the symptoms are very often miscellaneous. Statistics show that 80% of the brown recluse spider bites are misdiagnosed. A test has been created to identify the wound and the venom type, but the practice is not part of the medical routine yet. The next thirty six hours are crucial for the evolution of the condition, since it is now that a deterioration or an improvement may occur; generally speaking, the ulcer and the necrosis will only appear within a few days if the health status does not improve. Once the venom has got into the system, there is a whole range of symptoms that accompany the brown recluse spider bite: vomiting, nausea, fever and muscular or joint pain have been among the most frequently reported. How can one actually recognize a brown recluse spider? When you see a brown recluse spider for the first time it is impossible not to notice how much it resembles a violin; it is actually known as the fiddle-back spider or the violin spider for the color pattern it has on the back and bottom areas. Though the color specific to the species is brown, there are yellow and black varieties too, nevertheless, these color patterns are not a general characteristic of the brown recluse spider. Surprisingly enough, the death risk is a lot lower with this species; the explanation for this queer fact lies in the shy nature of the brown widow spider that injects venom timidly unlike the black widow. One common way to detect the presence of the brown widow spider is by identifying its egg sac. This is a peculiarity of the species, completely different from that of other widow spiders.