Tetrastichus sp. (Hymenoptera: Eulophidae) is a primary parasitoid of the Metisa plana (Lepidoptera: Psychidae), an oil palm bagworm. The sensilla on the surface of the antenna and ovipositor of Tetrastichus sp. were examined using a scanning electron microscope. The antennae of both male and female Tetrastichus sp. are geniculate in shape and hinged at the scape-pedicel joint. The female antenna is about 200 µm longer than the male antenna. However, the male antenna has an additional flagellomere compared to the female antenna. In total, eight different types of antennal sensilla were observed on the antenna of Tetrastichus sp.: trichoid sensilla type 1, 2, 3, 4, placoid sensilla type 1 and 2, basiconic sensilla, and campaniform sensilla. The antenna of the female Tetrastichus sp. lacks placoid sensilla type 2 and campaniform sensilla. The distribution and abundance of the antennal sensilla were compared between the male and female Tetrastichus sp. and discussed. On the ovipositor stylet of Tetrastichus sp., coeloconic sensilla, styloconic sensilla and campaniform sensilla were observed. Trichoid sensilla were observed at the medial part of the distal extremity of the ovipositor.

四叶草属 （膜翅目：Eulophidae）是油棕袋虫（Metisa plana）（鳞翅目：Psychidae）的主要寄生蜂。Tetrastichus sp.触角和产卵器表面的感受器。用扫描电子显微镜检查。雄性和雌性Tetrastichus sp.的触角。呈膝状并在花梗关节处铰接。母天线比公天线长约 200 µm。然而，与雌性天线相比，雄性天线具有额外的鞭毛。在Tetrastichus 的触角上总共观察到八种不同类型的触角感受器sp.: trichoid sensilla type 1, 2, 3, 4, placoid sensilla type 1 and 2, basiconic sensilla, and campaniform sensilla. 雌性Tetrastichus sp.的触角。缺乏板状感器 2 型和钟状感器。比较了雄性和雌性Tetrastichus sp.触角感受器的分布和丰度。并进行了讨论。在Tetrastichus sp.的产卵管丝上观察到腔状感受器、柱状感受器和钟状感受器。在产卵器远端的内侧部分观察到毛状感受器。