Ummidia – Trap-Door Spider

Ummidia is a genus of spiders that can be found around the world. Among other genus, they are commonly called trapdoor spiders because they build underground tunnels that are secured with a trap-door.

Ummidia Spider Description

The color of Ummidia spiders ranges from very dark brown to a lighter reddish brown. Their cephalothorax is shiny and hard while their abdomen is usually brighter and hairy. They are fast runners and have two large fangs to catch prey. For humans, their bites aren’t usually dangerous.

Ummidia trapdoor spider
A Cork-Lid Trapdoor Spider found in Hernando, Mississippi. Photo by Alicia

Size

On average, a Ummidia spider reaches a body size of around 1 inch. However, some specimen can grow up to a size of 1.6 inches.

Web

As mentioned above, trapdoor spiders do not create a web like other spiders. They build underground tunnels and secure the entrance to it with a door that can be closed with a hinge. The trapdoor is made of the spider’s silk material.

Trapdoor spider nest
The open entrance of a trapdoor spider’s nest. Photo: Flickr

Bite

Trapdoor spiders are not aggressive spiders and usually run away into the underground before any human can get close to them. In the rare cases in which a bite occurs, they are only mildly painful and not dangerous.

Ummidia scientific classification

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Subphylum: Chelicerata
  • Class: Arachnida
  • Order: Araneae
  • Infraorder: Mygalomorphae
  • Family: Halonoproctidae
  • Genus: Ummidia

Ummidia Distribution in the US

There are several species of Ummidia that can be found throughout the entire world. Therefore, Ummidia trap-door spiders can be found in every US state: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming

Ummidia – Trap-Door Spider

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