Rare: seldom seen or found.
Rasorial: formed for scratching; applied to leg structures.
Ravenous: greedy; voracious; hungrily.
Receptaculum seminis: a sac or pouch-like appendage at the junction of the oviducts with the vagina; it is filled during copulation and the eggs are fertilized from it as they are extruded.
Reclinate: directed backward; e.g. the bristles in Diptera.
Reclinatus: = reflexed; q.v.
Reclivate: curved into a convex, then into a concave line.
Recondite: the sting when concealed in the abdomen.
Rectal cauda: the terminal, tubular process or tail terminating the abdomen of some male Hemiptera.
Rectal glands: appendages to or thickenings of the rectum secreting a lubricating material.