Lunar Caterpillar, study for book Concealing Coloration in the Animal Kingdom

Thayer's lunar caterpillar study completes a trio of camouflage illustration studies at the Smithsonian, part of his systematic documentation of concealing coloration in insects. The Actias luna larva — the caterpillar of the luna moth — was of particular interest to Thayer because its green coloring against foliage demonstrated the principle of general background matching, as opposed to the disruptive patterns of the other subjects. Together these three Smithsonian studies represent the scientific dimension of Thayer's practice, which would eventually lead to his foundational work on animal camouflage.

Thayer renders the luna caterpillar's vivid green with the precision of a botanical illustration, capturing the soft, slightly translucent quality of the larva's body against a plain background. The execution is controlled and smooth, with accurate rendering of the larva's segmented form and the subtle variations in its green coloration.