Michael & Patricia Fogden, Animals and their colors camouflage warning coloration, courtship and territorial display mimicry, New York, Crow, 1974.

Adventitious disguise is ‘acquired’ disguise, and describes the habit that some animals have of covering themselves with soil, leaf fragments, bark, seaweed or other debris from their surroundings. Adventitious disguise not only produces a literally perfect resemblance to particular surroundings, but also gives a greater freedom of choice of surroundings to species which are neither polymorphic nor able to change colour. Caddis-fly larvae, for example, build themselves portable tubular cases with sand-grains when they live in fast-flowing stream, and with tiny pieces of wood and leaves when they live in sluggish stream or pond