In North America, the spiders in the infraorder Mygalomorphae include tarantulas and trapdoor spiders. They have two pairs of book lungs, usually two pairs of functioning spinnerets and their fangs or chelicarae are parallel to each other. In general Mygalomorphae are large spiders that do not use silk to trap prey. They also lead a solitary existence and typically inhabit burrows. These burrows are lined with silk and usually have some form of trapdoor, collar or turrent over the entrance. When these spiders are hunting the door is left open allowing the spider to dart out and attack any nearby prey that is sensed by vibrations in the surrounding substrate. (Ubick, 2005)
Classification:
The infraorder Mygalomorphae is subdivided into 6 families, of these only one family (Antrodiaetidae) is present in Alberta. Spiders in the family Antrodiaetidae are known by the following common names: trapdoor spiders, turrent spiders, and foldingdoor or collardoor spiders. Within this family, Alberta has only one species: Antrodiaetus pacificus (Simon) a folding-door spider.