stealthy ground spiders

Gnaphosidae is a large family of true spiders known as stealthy ground spiders. There are 2,583 species of ground spiders in 164 genera worldwide, at least 76 species in 22 genera in North America north of Mexico, and at least 31 species in at least 11 genera in Minnesota. They are found in grasslands on or near the ground, on tree trunks, and under stones.

Neither males nor females construct hunting webs. Both sexes spin tube-shaped retreats under stones, in bark, or in rolled leaves. They are fast runners. They hunt by pursuing their prey on the ground and immobilizing it with a thick, gluey, silk strand.

Gnaphosidae are medium-sized spiders ⅜″ to ⅝″ (10 to 15 mm) in length. The carapace is oval and usually unmarked. The anterior median eyes are dark. The posterior median eyes are oval and angled. The abdomen is elongated and slightly flattened. On all but one genus, the front spinnerets are tube-shaped and are visible from above. The legs are medium-length, stout, and spiny. All of the legs are about the same length. There are two claws at the tip, but these are not visible without magnification.

Sources

24, 29, 30, 82.

Location: Woodbury, MN