To continuously monitor ovipositor movements a new actograph was devised; it was composed of a radioelement glued at the ventral tip of the ovipositor, a scintillation probe to detect ovipositor movements and a microcomputer to store and process data. Immature and mature virgin females were able to perform ovipositor movements. The removal of the ovaries did not prevent the onset of ovipositor movements. The removal of the corpora allata carried out 6 to 8 days before imaginal moult prevented the onset of these movements. Injections of JH III restored the ovipositor movements previously abolished by allatectomy.