The families of British spiders

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L. Watson and M. J. Dallwitz

Pholcidae

Cellar Spiders, Daddy-long-legs Spiders.

Morphology. The adult spiders 2–10 mm long; slender-bodied; decidedly long-legged, or harvestman-like with very long, thin legs more than five times the body length; with eight eyes. The eyes in two horizontal rows of 4 (with a distinctive arrangement, the median pair of the front row of four being very small and flanked by horizontally elongated laterals, and the paired, somewhat longitudinally-elongated members constituting the posterior row being large). The chelicerae fused at the base. The palpal organs of the male of complex structure and enclosed by the specialized, hollowed tarsal segment (the cymbium). Metatarsus IV of the females without a calamistrum. Tarsal claws 3. The abdomen conspicuously patterned dorsally. The abdomen of the females without a cribellum. The reproductive openings of the females associated with an epigyne.

The adults making snare-webs; constructing tangled webs (in which the spider hangs upside down, mostly in buildings); Pholcus occasionally leaving the web to prey on other spiders, sometimes using the same technique of deception as Mimetidae (q.v.). The females carrying egg sacs via their chelicerae and palps.

British representation. 2 species in Britain; in the genera Pholcus and Psilochorus. Widespread (in England).

Comments. The legs extremely long, those of the first pair four to five times the body length; and the tarsi flexible and falsely segmented.

Illustrations. • Pholcus phalangioides.


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’.

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