The larvae ofTrinotoperla irrorata Tillyard(Gripopterygidae) possess remarkable chlorid cells consisting of one central cell and at least one adjacent cell grouped together into a small cell complex. They are termed floriform chloride cells because of the flower‐bud‐like structures seen by scanning electron miroscopy. Fine structural studies in combination with histochemical demonstration of chloride indicate that these cell complexes probably participate in osmoregulation by the absorption of salt.