VENOMOUS SPIDERS OF THE U.S. BY SCIENTIFIC NAME

Let me start by saying that I am not an arachnologist, nor am I an entomologist. These pages are designed to give limited information about the dangerously venomous spiders of the United States, but should in no way be considered a complete guide.

In reality, virtually every species of spider is venomous. All of them have fangs and inject venom to kill or paralyze their prey, however, most species do not have potent enough venom to be considered dangerous to humans. This page is designed to help identify those species of spiders in the United States that have potent venom, and could be considered dangerous or of medical significance.

All spiders belong to the following taxonomic groups.

Domain: Eukarya (Plants, animals, fungi, and protists)
Kingdom: Animalia (Animals)
Phylum: Arthropoda (Arthropods)
Class: Arachnida (Arachnids)
Order: Araneae (Spiders)

Below is a list of the venomous spiders that are found in the United States, with their scientific classification within the order Araneae. Click on the common name of the spider for information about that spider.

Family: Theridiidae
- Genus: Latrodectus (Widow Spiders)
  - Species: Latrodectus variolus - Northern Black Widow
  - Species: Latrodectus mactans - Southern Black Widow
  - Species: Latrodectus hesperus - Western Black Widow
  - Species: Latrodectus geometricus - Brown Widow
  - Species: Latrodectus bishopi - Red Widow
Family: Loxascelidae
- Genus: Loxosceles (Recluse Spiders)
  - Species: Loxosceles apachea - Apache Recluse
  - Species: Loxosceles arizonica - Arizona Recluse
  - Species: Loxosceles palma - Baja Recluse
  - Species: Loxosceles blanda - Big Bend Recluse
  - Species: Loxosceles reclusa - Brown Recluse
  - Species: Loxosceles laeta - Chilean Recluse
  - Species: Loxosceles deserta - Desert Recluse
  - Species: Loxosceles kaiba - Grand Canyon Recluse
  - Species: Loxosceles martha - Martha's Recluse
  - Species: Loxosceles rufescens - Mediterranean Recluse
  - Species: Loxosceles russelli - Russell's Recluse
  - Species: Loxosceles deviaTexas Recluse
  - Species: Loxosceles sabinaTucson Recluse
Family: Agelenidae
- Genus: Tegenaria (House Spiders)
  - Species: Tegenaria agrestis - Hobo Spider or Aggressive House Spider

Another group of spiders, from the genus Cheiracanthium, has been reported as having a painful bite sometimes resulting in an open wound (called a necrotic lesion) similar to those caused by the bite of Loxosceles spp. or Tegenaria agrestis. In some cases, systemic effects (i.e. headaches or nausea) were reported as well. At least two species of Cheiracanthium spp. exist throughout the United States:

Cheiracanthium meldei - Black-footed Spider
Cheiracanthium inclusum - Yellow Sac Spider

For more information on dangerously venomous spiders, please see the Venomous Links page.

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