An Etymological Dictionary of the German Language/Käfer
Käfer, m., ‘beetle, chafer,’ from the equiv. MidHG. këver, këfere, OHG. chëvar, chëvaro, m.; comp. AS. čeafor, E. chafer, Du. kever, m. The Goth. term was probably *kifra, or following AS. ceafor, *kafrus also (comp. LG. kavel). The name, which has the same import in all the dialects at their different periods, signifies ‘gnawing animal’ (comp. MidHG. kifen, kiffen, ‘to gnaw, chew,’ MidHG. kiffel under Kiefer), or ‘husk animal,’ from OHG. chëva, ‘husk,’ MidHG. kaf, E. chaff (AS. čeaf).