GROUND-BEETLE. A beetle of one of the largest and most important families of beetles, Carabida' (q.v.), so called because they live on or beneath the surface of the soil. About 12,000 spe cies have been described in this family, and 1100 of them occur in North America. Most of them are predaceous and carnivorous, and both adults and larva are swift runners. Their colors are dull metallic blue, green, brown, or black, and they are often ornamented by longitudinal ridges and rows of punctures. Both adults and larva' feed mainly upon insects, slugs and snailg, but also eat dead animal flesh. Some forms eat young growing corn, young seeds, and ripe strawberries. The family is generally useful to agriculture, for its various members feed on such destructive forms as the potato-beetle and its larva', the June beetle and cutworm. Certain species even ascend trees in search of canker-worms and plum-curculios. Seashore forms feed on the beech flea (Gammarus). A number of blind species inhabit caves both in Europe and America (see CAVE ANIMALS), and other small blind forms dwell under large stones. Not one of this last class has ever been found above ground, so that each colony may have been confined for genera tions under its respective stone. Certain other species live under stones at the seashore, which are covered at each high tide, and come out only when the tide is low. Still others occur in the nests of termites; these so strongly re semble the termite queens that one may easily mistake the one for the other, and they prob ably prey upon the termites. Some forms pro
duce a loud noise by raising the tip of the abdomen and rubbing it against a file on the wing-eases. These are the `squeakers' that are sold in Covent Garden market, London. Some forms are aquatic, and others live in wet sands of rivers and pools. Certain adult and larval forms lie awaiting their prey in holes in the ground, from which they bound out when the victim is sufficiently near. The overpoweringly fetid odor of a small species pygnurus) is described by Barrows (Proc. Assoc. Econ. Ent., Washington, 1897). In the United States the ground-beetles can only be confused with the darkling beetles (Tenebrionidu) of California ; the ground-beetles have five-jointed tarsi, while the darklings have only four joints in the hind tarsi. The 'searcher' (Calosoma scrutator) is one of our commonest ground-beetles. It is vio let, blue, and green, with red margins on the wing covers, and sometimes ascends trees in search of caterpillars. The bombardier-beetle (Lebia grandis), which closely resembles the bombar diers and is frequently an enemy of the potato beetle, and the genus Harpalus, are other common ground-beetles. The, last named are black, and feed to a considerable extent on cutworms.