PHOTORECEPTOR CELL RESPONSE AND FLICKER FUSION FREQUENCY IN THE COMPOUND EYE OF THE FLY, LUCILIA SERICATA (MEIGEN)

1. That part of the ERG which orginates in the retinula cells of the compound eye in Lucilia sericata was isolated without interfering with components originating in the optic ganglion. The retinula cell response is predominantly a sustained, cornea-negative wave, but in half the cases studied a brief, cornea-positive wave at "on" was also present.2. Electrical events which originate in the optic ganglion produce negligible potential difference between the cornea and the basement membrane of the ommatidial layer. Therefore, an electrical effect, per se, of an optic ganglion process on the retinula cells is very improbable.3. The electrical response of the retinula cells, uninfluenced by electrical fields produced by the optic ganglion, can resolve flicker stimuli of 200/sec. or higher.