The Sac Spiders of Canada and Alaska

Download or read book The Sac Spiders of Canada and Alaska written by and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many of the members of this group are nocturnal, spending the daylight hours in the sac, whereas others are active in daylight or darkness and live mainly in the dimness between layers of plant litter in forests, bogs, or swamps. [...] The principal mouthparts and the legs project to the front or sides from the membrane joining the edges of carapace and sternum. [...] The book lungs open through a pair of slits at the lateral ends of the genital groove, and the tracheae open through a common tracheal spiracle (rrsp) located either immediately anterior to the spinnerets (spin) as in the Clubionidae (Fig. [...] Sac spiders are defined as those spiders in which the chelicerae close toward the midlini, the eyes are arranged in two transverse rows, the legs are prograde and bear two tarsal claws, the anterior spinnerets are close together and not more heavily sclerotized than the posterior spinnerets, and the palp-coxal lobes lack a depression on the ventral surface. [...] Measurements given in this work include total body length, measured from the anterior margin of the carapace to the anal tubercle, to the nearest 0.05 mm; carapace length, measured from anterior to posterior ends of the carapace along the middorsal line; and carapace width, measured at the point of greatest width in dorsal aspect.