The ultra_morphology and chemical composition of waxes secreted by the scale insect Physokermes shanxiensis (Homoptera: Coccidae) was researched with the techniques of scanning electron microscope (SEM), infrared absorption spectra (IR) and gas chromatography/mass spectrometry (GC/MS). The result indicated that the scale insect secreted wet wax in its nymph stage. The wet wax coagulated into translucent wax covering on the body surface. However, the female adult secreted its wax secretion with white color and long thread form. According to the infrared absorption spectra characteristic of the waxes, it can be known that the both waxes either from male nymph or female adult were composed by a series of saturated and unsaturated long carbon chain compounds. But the two waxes have different in the chemical functional groups kind and numbers that composed the compounds, because of the differences in absorption peaks numbers and forms which appeared in the two infrared spectra from the wave number 1 800 cm -1 to 1 000 cm -1 . Through detected with GC/MS, 14 compounds with carbon atom number form C 13 to C 32 were obtained form the wax of the male scale insect. These compounds included 5 saturated higher fatty acids, 1 unsaturated higher fatty acid, 1 saturated higher fatty alcohol, 1 unsaturated higher fatty alcohol, 1 unsaturated ester, 1 saturated aldehyde, and 4 saturated alkane compounds.
