The predatory stink bugs are well known by their behavior, but the knowledge of the immature morphology and their natural history are scarce. Studies on predatory stink bugs are important to better understand their evolution and their use as biological controllers. Here, we describe the morphology of egg and the five nymphal instars of Oplomus catena (Drury, 1782), using optical and scanning electron microscopy. In general, O. catena immatures are very distinctive from other Asopinae species already studied. The egg is black, with short aero-micropylar processes and similar to those described for Stiretrus species. The nymphs can be diagnosed by the abdominal plates very large and bright blue. The color polymorphism of adults is fully illustrated, and four color patterns are proposed. The natural history of the species is described based on field and laboratory observations. The known prey of the species is reviewed and new preys are reported. The morphological and biological traits here described are discussed in order to better understand the biological role of predatory stink bugs.

中文翻译：

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成年幼虫的形态学，成人的染色体多态性和Oplomus catena（Heteroptera：Pentatomidae：Asopinae）的自然史。

掠食性臭虫的行为众所周知，但是对未成熟形态及其自然历史的了解却很少。对掠食性臭虫的研究对于更好地了解它们的进化及其作为生物控制器的用途非常重要。在这里，我们使用光学和扫描电子显微镜描述卵和Oplomus catena的五只若虫幼虫的形态（Drury，1782年）。通常，未成熟的O. catena与其他已经研究过的Asopinae物种非常不同。鸡蛋是黑色的，具有很短的气孔形成过程，与Stiretrus所述的相似种类。若虫可以通过腹板很大而明亮的蓝色来诊断。成年人的颜色多态性得到充分说明，并提出了四种颜色模式。根据田野和实验室观察来描述该物种的自然历史。对该物种已知的猎物进行审查，并报告新的猎物。为了更好地了解掠食性臭虫的生物学作用，对此处描述的形态和生物学特性进行了讨论。