deer fly in Finnish

A louse fly, a species 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, found in Eurasia.

A gold- or green-eyed horsefly of the genus Chrysops in the family Tabanidae; pests to cattle, horses and humans, feeding on their blood.