from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Protective coloration in an animal or insect, characterized by darker coloring of areas exposed to light and lighter coloring of areas that are normally shaded.
Sorry, no etymologies found.
According to Wagner Caterpillars of Eastern North America, Princeton Field Guides, 2005, the graded lightening of the sides of this caterpillar's body from the top to the bottom is an example of countershading.
This “countershading” helps soften shadows beneath them so that predators have a harder time distinguishing them as three-dimensional objects.