Robust beetles, variable in shape, oval to somewhat elongated, usually convex, but some compressed. In some groups males have prominent horns on head or pronotum--these are used in intraspecific struggles over mates or resources.
Characteristics:
front tibia widened with outer edges toothed
antennae 10 (sometimes 9) segments
antennae have club of last 3-7 segments, flattened to form plates (lamellae) that can be expanded or folded together
Tarsal formula usually 5-5-5, but front tarsi sometimes absent.
