calamistrum

The calamistrum is a specialized comb-like structure found on the hind legs of certain spiders. It is located on the metatarsus of the fourth leg. This comb aids in organizing the silk produced by the cribellum, a spinning organ. When silk flows from the cribellum, the calamistrum combs it, creating a distinct, woolly texture. This unique adaptation is characteristic of comb-footed spiders, such as the black widow. Spiders, as a group, are true silk specialists, using silk for various purposes including prey capture, draglines, and egg sacs. Their bodies are divided into a cephalothorax and abdomen, with legs attached to the cephalothorax.123