An Etymological Dictionary of the German Language/Annotated/Raupe

by Friedrich Kluge

Raupe (1.), feminine, ‘caterpillar,’ from Middle High German rûpe, rûppe, Old High German rûpa, rûppa, feminine, ‘larvæ of insects, caterpillar.’ In Suabian and Bavarian (partly also in Swiss) the word is wanting, the term used being Graswurm, in Old High German grasawurm (yet in Suabian ruopen, ‘to clear the trees of caterpillars,’ with an abnormal ů for û); in Swiss roup, which probably originated in the written language (in Henneberg abnormally roppe).

Raupe (2.) in Aalraupe is an entirely different word; see the latter.