Scientific Name
Trachelas tranquillus
Common Name
No official common name
Other Names
Broad-faced Sac Spider, Ground Sac Spider
Explanation of Names
- Author: Nicholas Marcellus Hentz. First year published: 1847, as Clubiona tranquilla.
- Pronunciation: Truh-KELL-us tran-KILL-us.
- Meaning: Trachelas is Latinized Greek for “necky,” which is meant to be a nickname for someone or something with a thick neck; tranquillus is Latin for quiet, calm, tranquil.
Appearance
- Size: Body length of mature female 7-10 mm; males 5-6 mm.
- Color: Carapace deep reddish brown. Abdomen cream to pale gray. First pair of legs thick and reddish brown; succeeding pairs of legs increasingly thinner and paler.
- Eyes: Eight eyes arranged in two rows rather evenly spaced across face.
- Legs: First pair thickest and longest. Third pair shortest. All legs are rather smooth and shiny looking, but are covered with tiny hairs not visible to the naked eye.
- Body: Rather robust, abdomen scarcely larger than cephalothorax.
Range
Minnesota to Nova Scotia, southward to Oklahoma and to northern Georgia.
Habitat
Prefers warm and dry places, at the base of plants or under stones or leaves, sometimes on trees or fences. Often found in silken retreats constructed in rolled-up leaves or occasionally under rocks. It frequently strays indoors in autumn.
Web
This is a hunting spider that does not spin a web for prey capture. It does use silk for the construction of egg sacs, retreats, and safety lines, though.
Season
Mature spiders are most noticeable in fall because they frequently stray indoors. Most mating takes place in summer and early fall.
Food
Prey is insects and other small animals that the spider can overpower without the aid of a web.
Life Cycle
This species is most active at night, as it hunts for prey. It may spend the daylight hours under leaf litter, tree bark, or sometimes in a silken retreat inside a rolled-up leaf. Male spiders typically reach maturity in mid-summer and mate thereafter. Adult females can be found all year round, even in winter. Females produce a white, lenticular egg sac in summer or fall, usually under loose tree bark or under a rock. The package is roughly 10mm in diameter and 2.5mm thick, containing roughly 30-50 eggs.
Comments
This spider can be mistaken for the Woodlouse Hunter, Dysdera crocata. The Woodlouse Hunter can be distinguished by its very long jaws and fangs. Both spiders can wander into homes on occasion. Trachelas is a member of the family Corinnidae, whereas Dysdera belongs to the family Dysderidae.
