Filum terminale

As Terminalfilum or terminal thread an unpaired appendix at the end of the abdomen of various insects is called. He does not represent a remnant of a limb pair, but is a form of the last abdominal segment, the telson.

Normally the Terminalfilum is long and filiform as in mayflies, but most insects do not have one. In addition to the Terminalfilum often occur on the last segment before the pygidium two pairs applied to other annexes, which are called Cerci.