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Silk apparatus of the funnel‐web spider, Agelena limbata was located at the ventral end of the abdominal part, and was composed of internal silk glands and external spinnerets. Among the three pairs of spinnerets, the posterior pairs were highly elongated along the body axis. By the light and electron microscopic inspections, it was found that four types of silk glands were connected through the typical spinning tubes of each spinneret. Anterior spinnerets comprise 2 pairs of the ampullate and 125 to 150 pairs (female) or 110 to 114 (male) of pyriform glands. Another 2 pairs of ampullate glands in both sexes, 5 to 8 pairs of tubuliform glands in females, and 20 to 26 pairs (female) or 15 to 17 pairs (male) of aciniform glands were connected on the median spinnerets. Additional 8 to 10 pairs of tubuliforms in female and 41 to 53 pairs (female) or 27 to 32 pairs (male) of aciniform glands were on the posterior spinnerets, respectively. While the ampullate and tubuliform glands were connected with the spigot‐type spinning tubes, the pyriform and aciniform glands with that of spool‐type tubes. It has been also revealed that the tubuliform glands were only observed in female spiders, however the flagelliform and aggregate glands which had the function of adhesive thread production in orb‐web spiders were not observed at both sexes of this spiders.

Capture threads of the golden orb-web spider Nephila clavata are produced from the silks of a pair of triad spinning units composed of a flagelliform gland (FLG) and two aggregate glands (AGG). In N. clavata, arrangement of the triad spigots is closely related to coating an axial supporting fiber with sticky aqueous droplets on a continuous and consistent basis for capture thread production. The central spigot of FLG and peripherally located AGG spigots are aligned along a single plane, and both have bullet-type spigots with flexible segments. In particular, the pear-shaped spigot of the AGG with a wide-aperture nozzle provides not only sufficient luminal space for controlling transient storage of the aqueous gluey substance but also an effective spatial system that thoroughly coats the axial fibers with a viscous aqueous solution.

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