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 grows to a horn-like extension, but even more bizarre and hard-to-describe shapes are also found. 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.