Source : Webster's Revised Unabridged Dictionary (1913)

Phalangoidea \Phal`an*goi"de*a\, n. pl. [NL., from Phalangium
   the daddy longlegs (see {Phalangious}) + Gr. ? form.]
   (Zo["o]l.)
   A division of Arachnoidea, including the daddy longlegs or
   harvestman ({Phalangium}) and many similar kinds. They have
   long, slender, many-jointed legs; usually a rounded,
   segmented abdomen; and chelate jaws. They breathe by
   trache[ae]. Called also {Phalangides}, {Phalangidea},
   {Phalangiida}, and {Opilionea}.