Specimens from 51 sheep and one goat were studied microscopically. Myiasis by Gedoelstia larvae occurred mainly in the organs of the head, neck and thorax, the eyes, brain, heart and blood vessels being most frequently involved. The fundamental lesion was thrombovasculitis which gave rise to glaucoma and other marked lesions in the eyes, infarction of the myocardium, lungs and kidneys and encephalomalacia in various parts of the brain. The migratory pattern of the larva appeared to be primarily intravascular, but extravascular routes such as those along the optic fasciculus and nerves of the head were also observed. The generic name, gedoelstiasis is introduced for this specific type of myiasis.