Abstract:Cellulase extract preparation from intestinal tracts of the Apriona germari Hope (Lamiinae, feeding in phloem, sapwood and duramen of mulberry trees), Anoplophora chinensis Forster (Lamiinae, feeding in the sapwood and duramen of various host plants) and Nedezhdiella cantori (Hope) (Cerambyciinae, living in the heartwood of citrus trees) were tested to determine the hydrolytic abilities of digestive enzymes on various subtracts: microcrystalline cellulose (MC), sodium carboxymethyl cellulose (CMCNa) and salicin. It revealed that all of the three species could hydrolyze all the subtracts mentioned. The results indicated that the three species of cerambycids all did have cellulolytic enzyme complex: exo-β-1, 4-glucanase (C1-ase ), endo-β-1, 4 glucanase (Cx-ase ) and β-1,4-glucosidase in the gut, and possess a real cellulolytic capacity. Moreover, the C1-ase activity of the heartwood feeding species N. cantori would be higher than that of phloem and sapwood feeding species A. germari and A. chinensis. All the Borers examined are living in healthy trees, and they rarely encounter or consume fungus-infected wood; from the cultures of intestinal fluid on MC or CMC-Na selecting medium, no cellulolytic fungi was found on MC medium and only few bacteria on CMC-Na medium. In the tissue and microsection of dissected intestinal tracts there were not any special myctocytes or structure for harboring extracellular microorganisms.Comparing with the cellulases‘ characters between the common cellulolytic fungi and the cerambycid Borers, difference was very evident. Based on these facts, it was suggested that at least some of cerambycids would be able to secret cellulases and the cellulase complex should be endogenous rather than exogenous.