We reexamined the seismic events originating from impacts of meteoroids on the lunar surface, as recorded by the Apollo lunar seismic network, in terms of (1) difference in temporal distribution between large and small impacts, (2) clustering of impacts in a two-dimensional space of the time of the year and the time of the month (lunar day), and (3) their relationship with terrestrial observations. The study led us to identify several distinct families of meteoroids impacting the moon. Most meteoroids producing small impact-seismic events appear to approach from retrograde heliocentric orbits, including many that are associated with well-known cometary showers. In contrast, most meteoroides associated with large impact-seismic events appear to approach from prograde orbits. Although some of them may also be cometary, the observation is consistent with a hyposthesis that many of them represent stony asteroidal material. A unique cluster of large-amplitude impact events observed in June, 1975, appears to be associated with the Taurid cometary complex, suggesting that the Taurids contain more massive or even denser objects than other meteor showers. The previously reported discrepancy between lunar and terrestrial metroroid-flux estimates may be due to the differences in lunar and terrestrial detection efficiency among various families of meteroids. ¿ American Geophysical Union 1987