warble fly

Any of several dipteran species (botfly family Oestridae or the family Hypodermatidae), widespread in Europe and North America. The warble flies Hypoderma lineatum and H. bovis, also called cattle grubs or heel flies, are large, heavy, and beelike. They deposit their eggs on the legs of cattle. The larvae penetrate the skin, migrate through the body, and produce a lump, or warble, on the animal's back. Mature grubs emerge and drop to the ground to pupate. Warbles contain breathing holes, which reduce the hide's commercial value. One species (Oedemagena tarandi) is a reindeer pest that also causes economic losses.

Learn more about warble fly with a free trial on Britannica.com.

The heel is the prominence at the posterior end of the foot. It is based on the projection of one bone, the calcaneus, behind the articulation of the bones of the lower leg. In the long-footed mammals, both the hoofed species (unguligrade) and the clawed forms which walk on the toes (digitigrade), the heel is well above the ground at the apex of the angular joint known as the hock. In plantigrade species it rests on the ground.

See also

• Achilles' heel
• Siegfried in the Nibelungenlied