Source : Webster's Revised Unabridged Dictionary (1913)

Tracheobranchia \Tra`che*o*bran"chi*a\, n.; pl.
   {Tracheobranchlae}. [NL. See {Trachea}, and {Branchia}.]
   (Zo["o]l.)
   One of the gill-like breathing organs of certain aquatic
   insect larv[ae]. They contain tracheal tubes somewhat similar
   to those of other insects.