Species of fly

Neolipoptena ferrisi, or the Pacific deer ked, is a species of fly from the family Hippoboscidae. They are blood-feeding parasites of the mule deer - Odocoileus hemionus, the white-tailed deer - Odocoileus virginianus & The Pronghorn - Antilocapra americana. They are found from British Columbia, Canada, to Baja California, Mexico.

They are often misidentified as ticks.

The female fly will produce a single larvae at a time, retaining the larva internally until it is ready to pupate. The larva feeds on the secretions of a milk gland in the uterus of the female. After three larval instars, a white pre-pupa which immediately forms a hard dark puparium. The pupa is usually deposited where the deer slept overnight. When the pupa has completed its pupation. a winged adult emerges and flies in search of a suitable host, upon which fly sheds its wings and is permanently associated with the same host. This is typical of most members of the family Hippoboscidae.