  We report on X-ray properties of the gamma-ray binary 1FGL J1018.6-5856 using
observations obtained with the Swift X-ray telescope. Using 54 observations
made between MJD 55575 and 55984, we find that the X-ray flux is modulated at a
period of 16.57 +/- 0.11 days, consistent with previous reports based on
gamma-ray data. We find that the X-ray maximum at phase 0 previously reported
may not be a persistent feature of the source: the dramatic increases at phase
0 were detected only for ~100 days and not thereafter. Rather, the persistent
sinusoidal maximum seems to be at phase 0.3--0.4, and is misaligned with the
gamma-ray (GeV) peak. We also find evidence that the source's X-ray flux is
correlated with the spectral hardness in the 0.5--10 keV band. Such a
correlation has also been reported in the gamma-ray binaries LS 5039 and LS
I+61d303 and can help us to understand the X-ray emission mechanisms of the
sources.
