HARVEST-BUG, the familiar name for mites of the family Trombidiidae, belonging to the order Acari of the class Arachnida. Although at one time regarded as constituting a distinct species, described as Leptus autumnalis, harvest-bugs are now known to be the six-legged larval forms of several British species of mites of the genus 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, sometimes intense, irritation by piercing and adhering to the skin of the leg, usually lodging themselves in some part where the clothing is tight, such as the knee when covered with gartered stockings. They may be readily destroyed, and the irritation allayed, by rubbing the affected area with some insecticide like turpentine or benzine. They are not permanently parasitic, and if left alone will leave their temporary host to resume the active life characteristic of the adult mite, which is predatory in habits, preying upon minute living animal organisms.