The (Estrus Boris, or Gad-lly of the Ox, is larger than either of the others. Its chest is dark-brown with a yellow patch on the back, and the rounded abdomen has alternate ringe of a brown and orange colour. The fatty and cellular substance beneath the skin of the ox is the residence of its larvae. The fly almost uniformly selects a young beak in good condition, and, alighting on the back n little on one side of the spine, it punctures the skin and drops one of its eggs into the perforation, and with it probably some acrid fluid which causes temporary but intense pain. The ox darts away, and runs bellowing over the field with his head protruded and his tail extended. his companions smarting from the same pain or dreading a similar . attack also gallop wildly in every direction, hastening if it be in their power to some pond or stream where their enemy is afraid to follow them. A small tumour—a warble—presently appears on the buck, which being carefully examined is found to contain a little white worm. This worm grows and assumes a darker colour, and becomes a perfect hot ; and there it remains abundantly nourished by the fatty matter around it until the following June, when it begins to eat its way through the wail of its cell. Many a bird aware from the imenai nem of the beast of what In going forward Is ready to seize the loot as it is forcing itself through the aperture which it has made, and the cattle too instinctively crowd to the water in order that the intruder may fall into the stream and thus be lost. In one of these ways the
great majority of the Inman perish, but a few reach the ground, speedily burrow into it, Lass through their chrysalis state, and The farmer does not pay the attention which he ought to those warbles. It is true that the cattle when the tumour has once formed do not appear to suffer any inconvenience from its existence, and the farmer is accustomed to associate with the appearance of a few warbles the certainty of the thriving condition of the beasts ; but he forgets the pain and terror which the animal has already suffered and that which it has yet to undergo, and he also forgets the deterioration of the hide. The hole made by the bat in its escape will apparently close, but not until after a considerable period has elapsed, and never with a substance so firm and durable as the first. It is easy to destroy the creature in its cell. The pressure of the finger and thumb will effect it, and while the beast will escape considerable annoyance the hide will not be damaged.
The goat and the different species of deer, and in fact almost all animals, have their peculiar tormentors, but the distinctions and habits of these varieties of the Walrus are not well known.