All spiders are predators that feed mainly on insects and small arthropods.  Only two species in the United States are considered dangerous to man: the black widow & brown recluse.  Fortunately (for us around here), dangerous species are native to southern climates and are rarely seen in northern states.

Centipedes are arthropods with long, flattened bodies.  They are not insects but more closely related to lobsters and shrimp.  Centipedes have segmented bodies and vary in color from light yellow to a reddish brown.  They're often called "100-leggers" but actually have only 15 pairs of slender legs.  House centipedes average about 1½ inches long but some grow to a whopping 3-4 inches!

Spiders and Centipedes are both beneficial in helping to control insects; however, most people consider them "creepy" and prefer not to see them around.  The good news is that spiders & centipedes do not attack people!