Abstract:With the frass samplied from the Masson pine plantation in South China, a preliminary study on the use of frass in the identification of certain forest insects was reported. The materials covered 3 orders 10 families including 11 species of insects that feed on Masson pine and 5 species on other plants. A key based on the morphological characteristics of the frass was constructed. In order to improve the accuracy of identification, some enviromental fators were also considered. Both the practical significance and the limit of the method were discussed.