Deer botfly
The name deer botfly (also deer nose bot) refers to any species in the genus Cephenemyia (sometimes misspelled as Cephenomyia or Cephenemya), within the family Oestridae. They are large, gray-brown flies, often very accurate mimics of bumblebees. They attack chiefly the nostrils and pharyngeal cavity of members of the deer family. The larva of Cephenemyia auribarbis, infesting the stag, is called a stagworm. The genus name comes from the Greek kēphēn, drone bee, and myia, fly.
Description
The larval stages of Cephenemyia are obligate parasites of cervids. Eggs hatch in the uterus of the female. She then flies close to the head of her host species and while hovering ejects her larvae into its nostrils. Larvae migrate to the base of the animal's tongue, where they mature in clusters to a size of 25 to 36 mm. After being ejected by the host, they pupate in soil (2 to 3 weeks) before emerging as a sexually-mature but non-feeding adult, which must quickly find a mate, since its life is short.