Abstract:The bethylid wasps, Scleroderma sichuanensis Xiao is a new natural enemy of the longhom beetle, Semanotus sinoauster (Gressitt), which is a destructive insect pest of the Chinese fir, Cunninghamia lanceolata (Lamb.) Hook. It was firstly found in Lu County Forest Farm of Sichuan Province in 1994. Under laboratory conditions, it can reproduce on a series of hosts such as longhom beetles, wasps and lepidopterous larvae.There are 3 to 4 generations during a year in Lu County. Winter is passed as adults in the pupal tunels. The adults are longevous, and the females have high fecundity and sex ratio. The developmantal threshold of the eggs is of 1 4.4℃ and the accumulative effective temperature is of 346 degree day.