HARVEST-BUG, the familiar name for mites of the family Trornbidiidae, belonging to the order Acari of the class Arachnida. Harvest-bugs are the six-legged larval forms of several British species of Trombidium. They are minute, rusty-brown organisms, barely visible to the naked eye, which swarm in grass and low herbage in the summer and early autumn, and cause considerable irritation by piercing the skin, often lodging themselves in some part where the clothing is tight. They may be destroyed, and the irritation allayed, by rubbing the affected area with some in secticide like turpentine or benzine. They are not permanently parasitic, and if left alone will leave their temporary host to assume the active life characteristic of the adult mite, which preys upon minute animal organisms.