Abstract
The free walking step patterns of the tettigonid Neoconocephalus robustus are described and compared with the predictions of a model for walking co-ordination developed for the stick insect. Regular absences of rear leg protractions are found when the animal has walked for some minutes. The relative phasing of leg protractions before and after isolated absences suggests that an absence is created by a failure to meet all the conditions required for a protraction and that a ‘central oscillator’ maintains its intrinsic rhythm during such an absence.