Chordodes formosanus is a horsehair worm that has the praying mantis as its definitive host.

These worms can grow up to 90 centimetres (35 in) long and can be extremely dangerous for their host, especially the praying mantis.

[1] Reproductively, they are dioecious, with the internal fertilization of eggs that are then laid in gelatinous strings.

The larvae have rings of cuticular hooks and terminal stylets that are believed to be used to enter the hosts.

Development into the adult form takes weeks or months, and the larva moults several times as it grows in size.