stagworm

from The Century Dictionary.

• noun The larva of one of several bot-flies which infest the stag.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) The larva of any species of botfly which is parasitic upon the stag, such as Œstrus actæon, or Hypoderma actæon, which burrows beneath the skin, and Cephalomyia auribarbis, which lives in the nostrils.