A species of insect parasites which are often very annoying. They are of minute size and have the mouth shaped like a sucker. They are found in thick woods on plants, and attach themselves to any animal that passes. They attach their sucker to the skin and work their way into the flesh, sucking the-blood. They multiply so fast that many horses and cattle die from exhaustion, due to loss of blood. The ox-tick, when filled with blood, is half an inch long. The water-tick, another variety, always lives in the water.