 The femoral chordotonal organ is mononematic.In contrast, in the amphinematic form, the extracellular material of the cap forms a dense, tubular sheath that surrounds the sensory cilium and extends all the way to the cuticle at the attachment site.In this form, the attachment cell contains both microtubules and actin-rich scolopale rods similar to those present in the scolopale cell.