Abstract: Atudy on the life history of the Large Chestnut brown Chafer was carried out in Shalato, Luho from 1955 to 1963. The larva of this chafer injures barley,wheat,pea, potato,corn and sugar beet,and the adult attacks forest trees. It is one of the serious pest of agriculture and forestry in the north-west of Szechwan. In Shalato,a complete life cycle of theis insect needs six years. The first five sinters are in the larval stages and the last winter passed over in adult stage only.The eggs hatch from late July to the bedinning of October.The egg stage lasts 45 to 66 days.Larval stage lasts more than 58 months. At the middle of October the larvae burrow down into a depth of more than 40 cm. In the soil where they pass the winter. At the middle of April in the secomd year, they begin to omve upward and feed on plants. After five winters, pupation takes place ot a depth of 12-14 cm below the surface of the soil. Pupal stage lasts about two months.From the late July to the beginning of September,the beetle emerges,it remains underground untill the beginning of May in next year. The swarm ing of the beetles may be found in the middle or latter part of May. As soon as the beetles crawld out from the carth, they fly toward the forest of pitchpine, on which they feed and copulate. At the eng of May, the female flies backward to the field and lay egge into the soil. Egge are often gathered in clusters, each containing 10-28 eggs.The adult stage lasts about ten mouths, and dies out at the period from the middle of June to the beginning of July.