Spiders, along with daddylonglegs, ticks, mites, and scorpions, belong to the class Arachnida. They are beneficial animals that feed on all sorts of arthropods, including insects. About 3,000 species of spiders are found in the United States. Spiders rarely bite people, and most species found in the world are harmless.
Copies of the Spider Booklet can be obtained from the College of Agricultural Sciences Publications Office.
The information sheets below discuss the commonly encountered Pennsylvania spiders and two species that are rarely encountered but medically important.