The spinning apparatus of Uloboridae in relation to the structure and construction of capture threads (Arachnida,Araneida)

Summary Besides the two axial fibers and the mass of cribellum fibrils, a third component is present in the capture threads of uloborids. This is a substructure originating from the paracribellum. It probably helps to fasten the axial fibers in their position. The axial fibers are secreted from the two glandulae pseudoflagelliformes whose spigots are situated on the posterior spinnerets. It is hypothesized that the cribellum fibrils become jammed and thus fixed between the axial fibers by periodical abduction and adduction of these spinnerets.