Myth: Hobo spiders are aggressive.
Fact: Once upon a time, an entomologist who shall be nameless wanted to write about the spider Tegenaria agrestis. "Agrestis" is a Latin word meaning "rural." But this gentleman didn't know much Latin, so he coined the name "Aggressive House Spider" for the species. Arachnologists suspected that the name was intended to encourage irrational fear of spiders, for reasons it is better not to speculate on. In any case, everyone who knew anything about the species realized how inappropriate that name was.
The species is not aggressive, except in that any predator shows aggression toward its prey, and any spider is liable to bite when trapped against one's skin. The species is not a true house spider; in fact, it cannot live permanently in buildings and is the only real example of that otherwise mythical idea that outdoor spiders wander into houses. Generally it is the males that do this wandering, and females are seldom found indoors. And finally, "aggressive" has nothing to do with the meaning of the scientific name.
This unacceptable, fake name was firmly rejected by both the entomological and arachnological common-names boards, but nevertheless it's been used in a number of publications. Evidently people would rather think that spiders are more dangerous than they really are! "Hobo spider" (from its common occurrence along railroad tracks and spread along transportation corridors) is the authorized common name.
Information on this web site is not a substitute for professional medical advice, and should not be used to diagnose or treat a medical or health condition. You should consult a physician as to any symptoms that may require diagnosis or treatment. Genuine spider bites can sometimes require medical attention, but beyond that, several medical conditions commonly mistaken for spider bite can be even more serious. If you have what appears to be a serious spider bite, please contact your health care provider or local emergency services. If you have the actual spider that bit someone, always save it for identification by a professional arachnologist.