Oestrus haemorrhoidalis Linnaeus 1758 Gasterophilus haemorrhoidalis (also called nose botfly or lip botfly) is a species of the genus Gasterophilus that lays eggs on the lips and around the mouth of horses, mules and donkeys.

First instar development: Penetrate epidermis of the lips of hosts and migrate into mouth.

Males possess a surstylus that abruptly tapers distally, with short surstylar setae that reach at most halfway to the sagittal plane.

In Equidae, third-stage larvae attach to the stomach, but also to the rectum, sometimes in great numbers.

Li XY, Pape T, Zhang D. Taxonomic review of Gasterophilus (Oestridae, Gasterophilinae) of the world, with updated nomenclature, keys, biological notes, and distributions.