COMBINATION OF PHYSIOLOGICAL AND ANATOMICAL METHODS FOR STUDYING EXTRAOCULAR PHOTORECEPTORS ON THE GENITALIA OF THE BUTTERFLY, PAPILIO-XUTHUS

This paper describes a combination of electrophysiological and anatomi cal techniques useful for characterizing sensory neurons in insects in our studies on the extraocular photoreceptors on the genitalia of the butterfly, Papilio xuthus. Genital photoreceptors were first electrop hysiologically identified by recording photoreceptor spikes in respons e to light stimulation of the genitalia. The precise location and ultr astructure of these photoreceptors were then studied by light and elec tron microscopy. Both electrophysiological and anatomical techniques e mployed here were rather classical, but, as shown in this paper, they appear to be particularly useful for systems where intracellular penet ration is difficult.