【目的】 柠条长角象Trigonorhinus sp.是内蒙古地区新发现为害中间锦鸡儿Caragana liouana Zhao Y. Chang & Yakovlev的蛀干害虫。为便于种群调查和分辨雌雄成虫，本文对柠条长角象雌雄性别的形态差异进行研究。【方法】 通过测量柠条长角象成虫体长、体宽和第6腹板以及腹部末端和鞘翅末端是否完全覆盖腹部腹板等形态特征，进行雌雄成虫个体判别。【结果】 采用独立样本t检验分析并比较发现，雌雄两性成虫体长（t=﹣0.294，P=0.771）、体宽（t=0.981，P=0.337）和体宽与体长之比（t=1.352，P=0.191）差异不显著。通过对柠条长角象雌雄成虫个体的体征观察发现，差异主要表现在：1）雌虫腹部末端于中央圆弧处凹入呈二裂形，雄虫腹部末端钝圆；2）雌性的第6腹板长度（0.48±0.01）mm明显较第5腹板长，而雄性（0.30±0.01）mm显著短，且雌虫第6腹板所占体长比例（0.16±0.01）mm大于雄虫所占体长比例（0.11±0.02）mm；3）雌虫鞘翅完全覆盖腹部末端，雄虫鞘翅未完全覆盖腹部末端。【结论】 仅依据柠条长角象体型大小鉴别雌雄成虫是比较困难的，但第6腹板形态上的差异可以作为柠条长角象雌雄成虫准确、快速鉴别的特征。

[Objectives]  To identify morphological criteria for sexing Trigonorhinus sp., an important wood-boring pest of Caragana liouana Zhao Y. Chang & Yakovlev. [Methods]  The following morphological characteristics of adult Trigonorhinus sp. were measured; body length, body width and length of the 6th abdominal plate, as well as whether the wing sheath completely covered the end of the abdomen. [Results]  1) The end of the abdomen of females is concave and bifid in the center, whereas that of males is bluntly rounded. 2) The 6th abdominal plate of females is significantly longer (0.48± 0.01) mm than the 5th plate of males which was significantly shorter [(0.30±0.01) mm]. The proportion of body length comprised by the 6th abdominal plate [(0.16±0.01) mm] is greater in females than in males [(0.11±0.02) mm]. 3) Wing sheaths completely cover the end of abdomen in females, but not in males. [Conclusion]  Although is difficult to sex adult Trigonorhinus sp. on the basis of body size alone, they can be readily sexed by the length of the 6th belly plate. However, definitive sexing requires examination of the external genitalia.