Firefly Photic Organ (image) Indiana University Caption A cross-section diagram of the adult firefly lantern shows photic (yellow) and dorsal (blue) layers, tracheae and tracheal end-cell complexes (purple), nerve axons (green), epidermis (red), the transparent cuticle (brown), and the clustered cells of the photic layer (orange circle). Credit BY MATTHEW STANSBURY, BASED ON R.F. CHAPMAN AFTER D.S. SMITH 1963 Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.