Agelenopsis – American Grass Spider

Agelenopsis, American grass spiders, are a genus of spiders that can be found around the world and in every US state. They are some of the fastest spiders in the United States and can be fun just to watch if you can trigger the web right.

Using a long piece of a weed or grass, try tickling the web as a bug would, if it was struggling across the web. If you do it right, the Grass Spider will run out with lightning speed, looking for a meal.

Then again, if you don’t mind seeing it, you can always throw a bug in its web.

Quick Overview: Agelenopsis – American Grass Spider
Medically significant: No
Body size: 3/4 inch (19 mm)
Main colors: brown, black
Range: Throughout the United States
Web: Funnel-shaped web

Agelenopsis Description

The abdomen is oblong, with long spinnerets at the end. Most species of the American Grass Spider have a pattern of stripes running from front to back. On the abdomen, there are often two white stripes, which are broken into many sections. The Cephalothorax on the other hand, has the lighter stripe running down the middle, dividing two dark stripes.

The grass spider is often confused with some similar looking species of the wolf spider or the American Nursery web spider. In the Pacific Northwest, the grass spider’s distribution overlaps with the related hobo spider (Eratigena agrestis) and the giant house spider (Eratigena atrica). Both of these spiders are also part of the funnel-weaver family (Agelenidae) and have a similar appearance to the grass spider. The best way to distingiush the grass spider from these species are the clear three lighter lines that run along the cephalothorax (head) of the grass spider. Hobo spiders and giant house spiders don’t have these longitudinal lines but other, less-distinctive markings.

Eyes

Grass spiders have eight eyes. The eight eyes are all similar-sized and form an oval shape. You can see a closeup photo of the grass spider eyes below:

Size

The bodies will grow to 3/4” (19 mm) from front to back, and approximately 1 ½” (38 mm) including the legs.

Web

They always spin their webs horizontally, creating a thick floor, which will feed into a funnel at one end. The spider hides in the funnel section, waiting for its next meal to crawl upon its web. However, the webs are not the sticky kind, which are used to trap prey. Instead, they trigger vibrations on the web, which the spider feels. The Grass Spider then uses its speed to charge and attack its prey.

Grass spider bites

The Grass Spider is considered quite harmless to humans. They stay in their webs and do not venture out unless forced to do so. A bite can cause some local swelling, redness and itchiness but is not dangerous.

Agelenopsis Scientific Classification

• Kingdom: Animalia
• Phylum: Arthropoda
• Subphylum: Chelicerata
• Class: Arachnida
• Order: Araneae
• Infraorder: Araneomorphae
• Family: Agelenidae
• Genus: Agelenopsis

Other common names

The Grass Spider is also known as the American funnel-web spider or funnel weaver. It is not to be confused with the Funnel Web Spider, which is a very dangerous spider in Australia. To limit confusion, we strictly stick to the name American grass spider or grass spider.

Distribution of the American grass spider in the USA

Various species of the American grass spider can be found throughout the United States – 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