The families of British spiders
Long-jawed Orb Weavers.
Morphology. The adult spiders 2.5–11 mm long; of medium build, or decidedly plump-bodied; diverse in form, decidedly short-legged, or with legs of medium length, or decidedly long-legged; with eight eyes. The eyes in two horizontal rows of 4; all clear and glassy. The maxillae longer than broad. The palpal organs of the male of complex structure and enclosed by the specialized, hollowed tarsal segment (the cymbium). The male palps with a well developed paracymbium. Metatarsus IV of the females without a calamistrum. Tarsal claws 3. Tarsus IV without a ventral comb. The abdomen conspicuously patterned dorsally (sometimes green). The epigastric furrow pro-curved between the lung slits. The abdomen of the females without a cribellum. The reproductive openings of the females associated with an epigyne (but very simple in form).
The adults making snare-webs, or not making snare-webs (Pachygnatha); when web-forming, constructing orb webs (with an open hub, often in damp marsh vegetation, strung horizontally or at an angle); in Pachygnatha, actively pursuing their prey (ground running).
British representation. 9 species in Britain; in the genera Pachygnatha and Tetragnatha.
Comments. The posterior margin of the chelicerae exhibits one or more teeth, the labium is swollen distally except in Pachygnathus, and the male palpus has an elongate, hairy paracymbium which is sometimes branched.
Illustrations. • Pachygnatha clercki. • Pachygnatha listeri. • Pachygnatha degeeri. • Tetragnatha sp.. See the next image for dissections. • Tetragnatha sp., dissections.
To view the illustrations with detailed captions, go to the interactive key. This also offers 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.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. The families of British spiders. Version: 4th January 2012. http://delta-intkey.com’.