Thorn bugs, due to their unusual appearance, have long interested naturalists. They are best known for their enlarged and ornate pronotum, which most often resembles thorns, apparently to aid camouflage. In some species, the pronotum is a horn-like extension, but can form more bizarre shapes. The specialised pronotum (or helmet) may not be simply an expansion of the prothoracic sclerite, but a fused pair of dorsal appendages of the first thoracic segment.