Abstract: Objective To observe and understand the morphology and structure of Acarophenax tribalii in order to create a new record of this mite in China. Methods The stored grain samples（rice and brown rice）were collected from the storage of lo? cal dwellers，and mites breeding in the products were isolated. Then mite samples were prepared and identified as the previous protocols，and the species was classified in accordance with Hughes. Results A. tribalii was detected in the grain samples. The light microscopic examination exhibited ovally shaped idiosoma of this species，and the abdomen of the male was more inflated than that of the female. By general view，the propodosomatal plate appeared triangle?like，and its anterior margin was covered by the gnathosoma. Leg I consisted of four segments，and its tibia and tarsus healing were fused into a stubby tibiotarsus. A tarsulus occurred at the end of leg Ⅱ，Ⅲ and Ⅳ，with a claw born at each leg. Conclusion The morphology and structure of A. tribalii are characterized. This may lay a basis for following study on this species.

Key words: Acarophenax tribalii；Acarophenaidae；Morphology；Acari；Grain

摘要： 目的了解小颚螨的形态结构特征，创建在我国发现此螨的新纪录。方法采集居民家中储藏的粮食（大米和 黑米），分离其中孳生的螨，并参照有关文献制作标本和进行螨种鉴定，并依据Hughes分类方法进行螨种分类。结果 在采集的样本中发现了小颚螨。光镜下观察，可见小颚螨躯体卵圆形，雄螨比雌螨更圆，且有膨腹现象，前足体板似三角 形，前缘覆盖颚体；足Ⅰ4节，跗节与胫节愈合成为粗短的胫跗节；足Ⅱ~Ⅳ5节，末端有1前跗节，每足具1爪。结论初 步了解了小颚螨的形态结构特征，为进一步研究此螨奠定了基础。

关键词: 小颚螨；小颚螨科；形态学；蜱螨亚纲；谷物