Pararesonance (PR) whistlers observed in the topside ionosphere by the Dartmouth receiver on Ogo 6 are examined. The study extends that of Walter and Angerami (1969) to higher frequencies and shows that the upper cutoff frequency of PR whistlers closely follows a 1/L4 dependence from 6 to 100 kHz (at L=2.90 and 1.37, respectively). Most PR whistlers are attached to paralongitudinal (PL) whistlers due, presumably, to intermode coupling. The 'walking trace', or unattached PR whistler, reported by Walter and Angerami is evidently unusual. The upper cutoff frequency follows 1/L4 whether attachment occurs or not. Rising sawtooth appendages starting at the upper cutoff frequency are frequently seen on PR whistlers. The required multivalued extensions, of the theoretical isofrequency curves plotted in travel time versus observing latitude by Walter and Angerami, to produce these appendages are given in the appendix, but their physical implication has not been investigated. The terms pararesonance (PR) and paralongitudinal (PL) are suggested as preferable to proresonance and prolongitudinal which have been previously used.