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A Guide to Common Singapore Spiders
by Joseph K H Koh
  Humped Spider
Zosis geniculatus (Oliver) 1789
 
close-up of female
Female
The abdomen in triangular in side view, humped in front with a pair of tubercles on the summit.

The spider spins a horizontal or inclined orb-web.
Classification: Family Uloboridae, Feather-Legged Spiders.
Habitat: Under bridges or in old garages and abandoned sheds.
Female: 5-7 mm.
Male: 4-6mm.
Distribution: Throughout the tropics.
The hub is lace-like and occasionally is traversed by a closely woven band of silk. Suspended in the web are egg-sacs which are pinkish and have characteristic horn-like projections. Insects trapped in the web are rolled with the hind legs and wrapped in silk. The bundle is eventually carried to the hub of the web and sucked dry.

diagram showing spines on legUloborids and several related families have a cigar-shaped plate (cribellum) on the underside of the abdomen, in front of the spinnerets. The upper margin of the second last segment (metatarsus) of the fourth leg is armed with a row of strongly curved spines known collectively as the "calamistrum" (arrowed in diagram, right). It is through the combined action of the cribellum and calamistrum that the bluish silk characteristic of the Uloborids is produced. The front legs of the Uloborids are extraodinarily long, often longer than the entire length of the body. Unlike other spiders, Uloborids do not possess venom glands.
  From "A Guide to Common Singapore Spiders" by Joseph K. H. Koh
BP Guide to Nature Series published by the Singapore Science Centre and sponsored by British Petroleum
© 2000 Joseph K H Koh