Grass spider

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American Grass Spiders
Pennsylvania Grass Spider.jpg
A. pennsylvanica female in web
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Family: Agelenidae
Genus: Agelenopsis
Giebel, 1869

see text

13 species

The American grass spiders are members of the genus Agelenopsis. They weave sheet webs that have a funnel shelter on one edge. The web is not sticky, but these spiders make up for that shortcoming by running very rapidly. The larger specimens (depending on species) can get up to approximately 19 mm in body length. They may be recognized by the arrangement of their eight eyes into three rows. The top row has two eyes, the middle row has four eyes, and the bottom row has two eyes (spaced wider than the ones on the top row). They also have two prominent hind spinnerets, and somewhat indistinct bands on their legs. They also have two dark bands running down either side of the cephalothorax.

Agelenopsis aperta, the American funnel-web spider, produces agatoxins. Their bite causes rapid paralysis in insect prey, though their venom is not medically significant to humans.


The genus name is a combination of Agelena (Eurasian grass spiders) a genus of similar spiders, and Greek -opsis "to look like". They are harmless spiders. Although most spiders use their webs to catch prey, the grass spider's web lacks adhesive ability. The spiders make up for that with their fast running.

The main distinction between Agelenopsis and its European cousin genus Agelena consists of the pattern appearing on the cephalothorax: the former possess two quasi-parallel lines from the eyes to the beginning of the abdomen. The latter ones have lines that are curved, irregular and often meet at the end. Another difference is the length of the front legs row in females, however, in males the comparison is too inconsiderable.


Other pictures[edit]


See also[edit]

Funnel-Web Spider

External links[edit]