The nymphal stages of members of this assassin bug genus (referred to generally as “Masked Hunters”) exude a sticky substance that covers their entire body, including the antennae and legs, to which their environment (dirt, frass, plant fragments, etc) adheres to, effectively rendering them invisible. This affords them protection against predation, and allows them to function as ambush predators themselves.
In the top image, the nymph was a resident of a termite and borer infested tree stump, so carries a livery of sawdust and wood fragments. The bottom image shows another individual with a soil- and leaf litter-based coating. With the final moult into adulthood and the addition of wings for mobility, the assassin loses its cryptic capabilities and assumes a more conventional appearance.