Urogomphi are projections found on the terminal abdominal segment of immature stages in diverse Coleopteran families. A comparative morphology of cassidine urogomphi is done. Two basic types are found: a heavily sclerotized blade-like form derived from the sternum and pleuron, and elongate processes derived from the tergum. The former type may serve a cutting function in leaf-mining and sheath-feeding cassidines. The latter number one, two and four and hold feces and/or exuviae. The phylogenetic implications of these variations are discussed.