Noun
A Eurasian species of louse fly in the family Hippoboscidae, Lipoptena cervi; parasites of elk, deer and other bovine animals, sucking blood and laying eggs in the fur of the host animals.
A gold- or green-eyed horsefly of the genus Chrysops in the family Tabanidae; pests to cattle, horses and humans, feeding on their blood.
Source: en.wiktionary.org