【目的】 臂金龟亚科Euchirinae是金龟科Scarabaeidae中极具观赏性的一类甲虫。目前我国已记录2属8种，分别是彩臂金龟属Cheirotonus 6种和棕臂金龟属Propomacrus 2种，均被列为国家二级保护动物并录入2021版《国家重点野生动物名录》。我国分布的臂金龟亚科种类稀少，且臂金龟亚科类群的生物学信息长期无法获取，导致类群间较为系统的形态学信息的收集和分类学研究进展缓慢，近缘种的鉴定工作存在很大的困难，对海关及公安部门的查验工作造成一定阻碍。本研究基于几何形态学对我国臂金龟亚科雌、雄个体的多种形态特征进行定量分析，揭示国内分布的8种臂金龟间的形态差异，筛选出更多在我国臂金龟分类和鉴定工作中可用的形态特征，同时为海关在臂金龟形态鉴定方面提供新思路。【方法】 基于几何形态学量化臂金龟亚科8种的前足胫节外轮廓，以及前胸背板和鞘翅的左侧外轮廓的形态学信息，利用主成分分析、典型变量分析和判别函数分析分别对8种臂金龟雌、雄个体的3个特征进行比较，探究种间雌、雄个体的形态差异，筛选鉴别特征。【结果】 基于主成分分析的结果，发现臂金龟亚科前足胫节在类群间的形态变化集中于刺突及胫节的弯曲程度，前胸背板变异部位在于后角的膨大及长宽比的缩小，鞘翅的变异在于肩角的向外延伸、靠近小盾片处鞘翅的内缩及长宽比的缩小。典型变量分析及判别函数分析的结果表明：雄性臂金龟的前足胫节的形态学信息在类群间具有更显著的差异，测试组间的判别正确率达100%的测试组占全部测试组的93%（26/28）；于占比最高的2个典型变量(CV1和CV2)所构成的形态空间中，臂金龟CV1和CV2在8种雌性的鞘翅的形态数据的分布并无交集。【结论】 前足胫节的形态学信息在8种雄性臂金龟的种间差异性更高，鞘翅的形态信息更利于进行种间雌虫的区分，几何形态学可以更好地挖掘出我国本土臂金龟亚科种间的形态差异并用于种间鉴定工作。

[Aim]  Euchirinae is a subfamily of Scarabaeidae, or scarab beetles. At present, two genera and eight species of Euchirinae have been found in China. These include six species from the genus Cheirotonus and two species from the genus Propomacrus, all of which have been listed as national second-class protected animals in the 2021 edition of the ‘List of wild animals under priority conservation’. The species of the subfamily Euchirinae distributed in China are rare, and the biological information of the subfamily Euchirinae has been difficult to obtain for a long time, resulting in slow progress in the collection and taxonomic research of systematic morphological information between groups. The identification of closely related species is also very difficult, which poses certain obstacles to the inspection work of customs and public security departments. Based on geometric morphometrics, our study quantitatively analyzed the morphological characteristics of male and female Euchirinae samples in China, revealing the morphological differences among 8 species of Euchirinae distributed in China. We also screened additional morphological characteristics for classification and identification. This study offers innovative approaches for improving the customs inspection process. [Methods]  Based on geometric morphometrics, we compared the outer contours of the protibia of eight species of Euchirinae, and the morphology of the left outer contours of the pronotum and elytron in both males and females, using principal component analysis (PCA), canonical variance analysis (CVA), and discriminant function analysis (DFA). The morphological differences between male and female individuals were analyzed, and the identification features recorded. [Results]  Based on the PCA results, we found that the morphological changes of the protibia in the intergroup segment of Euchirinae were concentrated in the curvature of the spines and tibia. Whereas variation in the pronotum resulted from the expansion of the posterior horn and the reduction of the aspect ratio. Finally, we found elytron variation was due to extension of the shoulder angle, the interaction of the elytron near the scutellum, and a reduction in the aspect ratio. The CVA and DFA results showed a significant difference in the morphology of the male protibia between species. Of the test groups, 93% (26/28) achieved a 100% discriminant accuracy rate between test groups. Finally, CVA analysis showed there was no intersection between the elytron morphology of the eight female long-armed scarabs. [Conclusion]  The morphological characteristics of the male protibia differed significantly between Euchirinae species. Furthermore, the elytrons of female samples exhibited stronger interspecific differentiation. Geometric morphometrics can facilitate the identification of morphological differences between Euchirinae species in China and be used for interspecific identification.