Fine structure of the tracheoles of the lantern of a photurid firefly.

The lantern tracheoles of the firefly, Photuris, are unusual in that their walls are reinforced by cuticular bars. The tracheoles are stiff and resist collapse under conditions which flatten more typical tracheoles. This reinforcement and the structural resemblance of the tracheal end cell to cells considered to be active in moving ions and fluid is taken as evidence suggesting that the flash may be turned on and off by control of the oxygen supply and that said control may involve some sort of osmotic mechanism.