While we are on the subject of spiders harmful to humans, in Wisconsin we do have the black widow. There are other spiders that are black with red markings, one of them being a jumping spider that is very often seen in houses. Some people have also heard of the brown recluse spider. That does not mean that it could not be brought into the area accidentally but it is quite unlikely that you would run into it. The thing to do if bitten by a questionable spider is to go to a doctor for treatment and try to save the spider responsible for identification.
Many people call the museum to ask whether a particular spider is poisonous.
Almost all spiders use venom to catch their prey, but only a few have a venom that could be harmful to humans. A small percentage of people have an allergic reaction, just as some people do to bee stings. The best attitude to take toward spiders, or for that matter any wild creature, is respect - not fear, not carelessness, but respect. Before we got sidetracked on venom we were discussing tarantulas. There is at least one other creature that has been called that.