Abstract: 【Aim】 The quantitative morphological differences of Protaetia (Liocola) brevitarsis from different geographical populations in China and the adjacent regions were compared. The morphological differences among the populations from Xinjiang and the adjacent regions were specially studied. The results can provide guidance for plant protection and production activities. Furthermore, this study will shed new light on microevolution theory. 【Methods】 The morphology of the pronotum and elytra of P. (L.) brevitarsis was studied based on 700 individuals from 30 regions of China using geometric morphometrics approaches. The geographical variations on morphology were analyzed based on principal component analysis (PCA) and canonical variate analysis (CVA). 【Results】 The specimens of  P. (L.) brevitarsis  from Xinjiang obviously clustered together in the PCA results of pronotum and elytra. There were some morphological overlapping between the specimens from Xinjiang and those from the adjacent areas, while there were little morphological overlapping between the specimens from Xinjiang and those from the areas far from Xinjiang. Additionally, the specimens from Xinjiang and those from south China were obviously separated in morphology. The significance testing for the morphological differences among the populations from different regions based on the Mahalanobis distance and Procrustes distance proved that there were significant differences between the specimens from Xinjiang and those from the areas far from Xinjiang in morphology. At the same time, there were no significant differences between the specimens from Xinjiang and those from other areas in Mahalanobis distance and Procrustes distance. 【Conclusion】 This study proved that the white spot on the pronotum and elytra can be a sound evaluation criteria for geographical variations of  P. (L.) brevitarsis . The geographical distance is related to the morphological distance in a certain degree. We assumed that  P. (L.) brevitarsis  possibly invaded Xinjiang from Ningxia, Inner Mongolia and Gansu outside the north border of Qinghai, and the source of P. brevitarsis  invading Xinjiang is the same with that invading these three provinces. This study demonstrated a research model which may have a broad prospect to enrich the microevolution theory and molecular ecology research.

Key words: Protaetia brevitarsis, geometric morphometrics, principal component analysis (PCA), canonical variate analysis (CVA), geographic variation