Source : Webster's Revised Unabridged Dictionary (1913)

Taenidium \T[ae]*nid"i*um\, n.; pl. {T[ae]nidia}. [NL., dim. fr.
   L. taenia a ribbon.] (Zo["o]l.)
   The chitinous fiber forming the spiral thread of the
   trache[ae] of insects. See Illust. of {Trachea}.