Spiders are not insects but belong to the class Arachnida, along with mites, scorpions, ticks, and harvestmen. All Arachnida have four pairs of legs and two main body segments; insects have three pairs of legs and three main body segments. There are many different kinds of spiders. Some spin intricate webs to trap their prey; others do not spin webs. Instead they actively hunt their prey or wait motionless and grab their victims as the victims approach. Most spiders in homes and gardens build neat, organized webs or sheets of webbing that lead into a funnel. The poisonous black widow and the brown recluse spiders both spin an irregular, tangled web in a dark, quiet location or among debris on the ground. Many nonpoisonous species also build tangled webs. Most spiders lay eggs in silken sacs. The young spiderlings resemble adults and are cannibalistic. Some spiderlings leave the egg sac by sending out a long silken thread that catches the wind and pulls the spider into the air. This process is called ballooning. In the fall, the air is sometimes filled with masses of these threads, called gossamer. Spiders feed mostly on insects, but they play only a minor role in controlling insect pests.
Knock down webs with a broom or duster. To help keep spiders from entering the home, seal cracks, inspect and repair window screens, and clean up any debris outdoors that may harbor spiders or their prey.