Urinary vessels: = malpighian tubules; q.v.: has also been applied by older authors, to anal glands.

Urite: an abdominal segment and, specifically, its ventral portion.

Uromere: any of the abdominal segments of an arthropod.

Uropoda: any of the abdominal feet of arthropods.

Uropygium: the ovipositor when it is a mere extension of the abdominal segments.

Urosome: the abdomen.

Urosternite: the sternal or under piece of the uromeres.

Urticating: nettling; applied to specialized hairs or processes on the bodies of certain caterpillars, which cause a stinging or burning sensation on the skin.

Ustulatus: scorched: applied to a maculation that has the appearance of having been burned in.

Uterus: the vaginal portion of oviduct: the sometimes enlarged portion of the vagina at junction of the oviducts: = calyx, q.v.