Camouflage strategies, including several types of concealments, are known for several insect groups today, such as immatures of some species within reduviid bugs (Hemiptera), lace wings (Neuroptera), caddisflies (Trichoptera) and bark lice (Psocodea). However, camouflage has only rarely been reported in the fossil record. Here we report findings of four bark lice preserved in 100 Million year old amber from Myanmar, which represent the first fossil evidence for masking behaviour in Cretaceous representatives of Psocodea. All four of these, probably not conspecific, and immature bark lice carry sand granules and organic material atop their back, which probably resulted in camouflaging them against the background (e.g. bark) to avoid detection by predators. We briefly summarise concepts of camouflage and examples of decoration behaviour within insects, as well as possible “receiver” (i.e. predators) of the camouflage of the herein described bark lice. The exact phylogenetic position of the specimens remains unclear, due to the scarce fossil record of Cretaceous immatures of Psocodea, as well as extant immatures. This demonstrates the importance of findings as reported here, as a wide knowledge of morphology and development of a certain group is crucial to get an insight into their evolution and reconstructing environments in deep time.

伪装策略，包括几种类型的隐藏，今天为几种昆虫群体而闻名，例如赤翅目昆虫（半翅目）、花边翅膀（神经翅目）、石蛾（毛翅目）和树皮虱子（Psocodea）中的某些物种的幼虫。然而，在化石记录中很少报道伪装。在这里，我们报告了保存在 1 亿年前缅甸琥珀中的四只树皮虱的发现，这是 Psocodea 白垩纪代表的掩蔽行为的第一个化石证据。所有这四种（可能不是同种的）和未成熟的树皮虱子的背上都携带沙粒和有机物质，这可能导致它们在背景（例如树皮）下伪装以避免被捕食者发现。我们简要总结了伪装的概念和昆虫内装饰行为的例子，以及本文描述的树皮虱伪装的可能“接收者”（即捕食者）。由于 Psocodea 白垩纪幼体和现存幼体的化石记录稀少，标本的确切系统发育位置仍不清楚。这证明了此处报告的发现的重要性，因为对某个群体的形态学和发展的广泛了解对于深入了解他们的进化和重建环境至关重要。