The Collaborative International Dictionary
grandfather longlegs
Daddy longlegs \Dad"dy long"legs`\
(Zo["o]l.) An arachnidan of the genus Phalangium, and allied genera, having a small body and four pairs of long legs; -- called also harvestman, carter, and grandfather longlegs.
(Zo["o]l.) A name applied to many species of dipterous insects of the genus Tipula, and allied genera, with slender bodies, and very long, slender legs; the crane fly; -- called also father longlegs.