Calamistrum

In spiders, the calamistrum is a row of specialized leg bristles used to comb out fine bands of silk.

[2] The calamistrum and cribellum are used to form the hackled bands of silk which are characteristic of the webs of these spiders.

[2] The calamistrum is found on the upper margin of the metatarsus of the hind legs.

The ratio between calamistrum length and cribellum width varies greatly, however, even among related species.

[3] When male cribellate spiders reach sexual maturity, they either lose the cribellum and calamistrum or retain them in a vestigial form.