The male of Libellula depressa translocates sperm after each successive seizure even if the copulation does not always follow. In contrast, the male of Aeshna cyanea does not translocate sperm to the penis again if it has not copulated after doing this on the preceding occasion. In Brachythemis contaminata the sperm translocated in one act can be used for several copulations. In B. contaminata and Nannothemis bella sperm translocation seems to normally occur in the male alone. It is suggested that while in-landem sperm translocation might imply the advantage for the male of fertilizing eggs with fresh sperm, selection for shortening the duration of the mating sequence in some species may have caused the shift of sperm translocation before the tandem formation.