Recurrent vein: in Hemerobiidae, the first branch of the subcosta when it recurves toward the base of the wing.
Recurved: bowed backward.
Reductus: a zig-zag marking or corrugation.
Reflected or Reflexed: angularly bent backward.
Refracted: bent back as if broken.
Region: a space or area adjoining a specified point: a part of the body composed of a number of segments, as the head, the thorax, or the abdomen.
Rejuvenescence: a renewal of youth; bringing back to a condition of youth.
Remote: further removed than distant.
Reniform: kidney-shaped: applied to a macula approximating that shape, found at the end of median cell in many moths.
Repand: wavy; with alternate segments of circles and intervening angles.