(Nephila), any of a genus of the class Arachnida (phylum Arthropoda), so named because of the great strength of their silk and the golden colour of their huge orb webs. These webs often measure one metre (about three feet) or more in diameter and are suspended between trees by guy lines. About 60 species are known to live in the warmer regions of the world. Adult females are very large with a body length of 25 to 50 millimetres (1 to 2 inches). Males are dwarfs, measuring only 4 to 6 mm. As adults they build no webs but rather live in the web of the female, where they are sometimes captured and eaten while attempting to mate. Juvenile silk spiders build complete orbs, whereas the older ones construct only the bottom portion, which is frequently repaired but not rebuilt every day, as in the case of most other orb weaver (q.v.) spiders.
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