The Deer Nasal Bots belongs to the genus Cephenemyia. These Bots are specific to the deer family (Cervids).
Nasal Bot Larvae begin life when the adult Bot Fly lays a group of eggs around the mouth or nose of a deer. The small larvae are released from the eggs when the deer licks them. The larvae then migrate to the nasal passages where they mature.
The mature larvae then move to the throat at the base of the tongue. Here they will grow to over an inch in length, and attach in clusters (usually of about 20) deep in the throat.
When the yellowish brown larvae have completed their development, they are expelled from the throat. The deer may snort or sneeze, blowing out these larvae which then burrow into the soil to pupate and in 2-3 weeks become adult flies.
The adult flies have no mouth parts for feeding so they are short-lived and must mate shortly after emerging, thus completing their life cycle.
They most often are found by taxidermists while preparing heads for mounting, although hunters occasionally notice them. Although Nasal Bots are quite large and unpleasant looking in the final stages of development, they cause little harm to the deer. Occasionally though, heavy infections may cause death by suffocation. Death may also result from detached larvae migrating to the lungs.
Lastly, Nasal Bots pose no disease threat to deer hunters and do not harm the venison. Remember, nasal bots are only found in nasal passages and around the mouth of deer. Deer “infected” with these harmless parasites are safe for human consumption, although I suspect many unknowing hunters have discarded carcasses after observing an ugly larvae crawling out of a deer’s nose.