Global auroral images from the ultraviolet imager on the Viking spacecraft are used to investigate spatially periodic bright spots on the dayside auroral oval that resemble beads on a string. The newly achieved temporal resolution of 1 min. or less in monitoring worldwide auroral distributions by the Viking imager contributes significantly to the capability of observing this phenomenon. It is found that these are frequently seen in the 1400--1600 MLT sector. The series of bright spots are not, however, limited to this unique local time sector, sinces they are seen to extend into the prenoon sector on some occasions. They occur often during substorm intervale but are also seen unaccompanied by substorm activities in the nightside. There is neither a consistent north-south nor east-west direction of motion for all the dayside bright spots observed so far. Our observation of the time scales for the transient intensifications of bright spots and the lack of consistent directions of their motion are consistent with the characteristics expected from the suggestion that these bright spots are related to the Kelvin-Helmholtz instability occurring within the magnetosphere. ¿ American Geophysical Union 1989