BioConcepts

imaginal diskImaginalscheibe (ger.)

• a relatively undifferentiated group of cells, present in the early stages of an insect’s development, which will develop into an adult organ before the final (imago) stage. (OED)  
  category metamorphosis

  1864

  Imaginalscheiben

  Weismann, A. (1864) Die Entwicklung der Dipteren: 135; cf. id. (1864). Die nachembryonale Entwicklung der Musciden nach Beobachtungen an Musca vomitoria und Sarcophaga carnaria. Z. wiss. Zool. 14, 187-336; cf. Sander, K. (1985). August Weismanns Untersuchungen zur Insektenentwicklung 1862-1882. Freiburger Universitätsbl. 24, issue 87/88,43-52.

  1874

  These collections of cells form flat disk-like bodies which are enclosed in a structureless membrane and may be termed the imaginal disks. In each imaginal disk of the thorax arises a quarter of a segment with the appendage belonging to it.

  Weismann, A. (1874). The metamorphosis of flies, I. Amer. Nat. 8, 603-12: 605.