taenidium

Century Dictionary and Cyclopedia

1. n. One of the chitinous fillets or bands which form either a part or the whole of the spiral thread surrounding the tracheæ of insects. This spiral thread is not continuous, rarely making more than two or three spiral turns, and sometimes forms a single ring or a short band. A. S. Packard.

Wiktionary

1. n. zoology The chitinous fibre forming the spiral thread of the tracheae of insects.

GNU Webster's 1913

1. n. (Zoöl.) The chitinous fiber forming the spiral thread of the tracheæ of insects. See Illust. of trachea.