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The MACHO database of photometry of the LMC has been examined for the field RR Lyrae star population. In this initial sample some 8000 stars are identified with the brightness, colors and periods of cluster variables. Bailey type ab (fundamental pulsators) and c (first harmonic pulsators) are identified with a global period ratio of P(1H)/P(F)=0.601 which falls wthin the range of Galactic field and cluster ratios. For the first time, RR Lyrae stars pulsating in the second harmonic are clearly identifiable with a period ratio of P(2H)/P(F)=0.490. These period ratios are consistent with standard evolutionary models of horizontal branch stars near 0.6 solar mass. There is low amplitude structure in the period distribution of the type ab stars bearing significantly on the origin of the Oosterhof dichotomy in Galactic RR Lyrae stars. There is little evidence in the LMC of the lacuna of Galactic stars with periods around 0.60 days and indeed there is no real indication of the Galactic Oosterhof types as predominant in this oldest LMC population. It is clear that the LMC RR Lyrae stars offer strong constraints on the morphology of the blue horizontal branch in the LMC and new insights into the kinematic and chemical correlations among subgroups within the Galactic halo.
