Fig. 3. Changes in ecdysis-triggering hormone (ETH)-immunoreactivity (IR) in sections of epitracheal glands during pupal and adult development. (A) The Inka cell showed very strong ETH staining (red colour) in pharate pupa approximately 3 h before ecdysis. (B) At the onset of pupal ecdysis, all gland cells decreased in size and most staining disappeared from the Inka cell. (C) Strong ETH-IR was again observed in the pupal Inka cell on day 3, but the other gland cells degenerated. (D) High peptide levels persisted in Inka cells throughout adult development, as indicated by strong ETH-IR in the pharate adult 1 day before ecdysis. (E) Adult ecdysis was associated with a marked decrease in ETH staining. Scale bar, 150 µm.