| | The spider families of Britain and Ireland |
~Dysderidae
Six-eyed Spiders.
Morphology. The adult spiders 6–22 mm long; of medium build; decidedly short-legged, or with legs of medium length (less than twice the body length); with six eyes. The eyes arranged as a pair of separate medians and two pairs of smaller laterals. The palpal organs of the male comprising an exposed bulb attached to the little-modified tarsal segment (no cymbium). Metatarsus IV of the females without a calamistrum. Tarsal claws 3. The abdomen conspicuously patterned dorsally. The tracheal spiracles behind the epigastric fold. The abdomen of the females without a cribellum. The reproductive openings of the females without an epigyne.
The adults constructing a terrestrial retreat in the form of a silk tube (this occupying a hole in a wall, in bark or under stones, and having up to twelve threads radiating from its lip); not making snare-webs (in the normal sense); lying in wait for their prey (the radiating threads serve as trip-wires for passing insects, to alert the spider lurking within its retreat).
Representation in Britain and Ireland. 3 species in Britain; in the genus Segestria.
Illustrations. • Segestria florentina. Segestria florentina (Rossi): a, female; b, chelicerae, maxillae, labium and sternum; c, front view of chelicerae and eyes; d, cephalothorax and chelicera in profile. From Blackwall (1864). • Segestria senoculata. Segestria senoculata (Linn.): a, male; c, female; d, two views of the male palpus. From Blackwall (1864. Note that the indicated size applies to the male). • Segestria senoculata. From Blackwall's Plate 29: being a second Fig. 270 labelled Segestria senoculata, cf. Plate 28, Fig. 270. The latter matches his description of the species better than this one, but this one compares better with Roberts's Plate 17. a, female; c, profile of cephalothorax and chelicera; d, front view of cephalothorax and chelicerae. From Blackwall (1864).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. The spider families of Britain and Ireland. Version: 5th August 2019. delta-intkey.com’.
