ox-warble
noun
1(More fully ox-warble fly) either of two flies of the family Oestridae, Hypoderma bovis and H. lineatum, whose larvae live under the skin of cattle.
2A swelling on the back of an ox caused by the larva of the ox-warble fly; the larva itself.
Origin
Mid 19th century; earliest use found in Jane Loudon (1807–1858), writer on botany and magazine editor.