Pest Information

Ground Spiders

Ground Spiders

  • Latin Name: Gnaphosa sp.
  • Common Name: Ground Spiders
  • Other Names: House Spider

Pest Details

Ground Spiders
Ground Spiders


These are primarily native species in North America.


This family of spiders contains many species in a number of genera, with the genus Gnaphosa one of the largest with over 20 species. These common spiders are medium in size but very fast running and commonly enter structures during or following their nocturnal activities. Because of their obvious presence and rapid movements they are a concern to homeowners. While they are capable of biting their venom is considered to be of no consequence to humans. They hide during the day under any available materials on the ground or floors, often resting within a silk tube that they have constructed.


Adult spiders are medium in size with a body length of about ½ inch. Their color ranges from black cephalothorax and dark gray abdomen to reddish orange cephalothorax and dark gray abdomen to more of an overall orange. Their spinnerets at the tip of the abdomen often are prominent, project backward, and under close examination are “barrel” shaped or cylindrical. There are 8 eyes arranged in 2 horizontal rows across the front of their flattened head area. They often show very large fangs that are tucked beneath the head while not in use.

Characteristicts Important to Control:

It should be recognized that these spiders are beneficial, and when found outdoors they are best left alone to serve as predators of insects. When found indoors the single spider can be controlled with a vacuum cleaner, and the use of a labeled residual insecticide around the exterior, particularly around doors and windows, will help to intercept them when they approach the structure. Keeping a perimeter around the foundation cleared of debris, foliage, and piled materials will prevent them from hiding close to the structure.

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