Phalangoidea \Phal`an*goi"de*a\, n. pl. [NL., from Phalangium the daddy longlegs (see {Phalangious}) + Gr. e'i^dos form.] (Zool.) 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}}. [1913 Webster]