The "American Black Widow" spider does not belong to a particular species. The phrase "black widow" really refers to a genus of venomous spiders called Latrodectus. The "Southern Black Widow" (Latrodectus mactans), which is often found in the southern and southeastern parts of the country, is the most well-known member of this group in the United States. The "Western Black Widow" (Latrodectus hesperus), which is found in the western states, is one of the numerous black widow species found in the US; however, the Southern Black Widow is the most well-known.