  Intra-Cluster Machos (ICMs) are a plausible candidate for at least some of
the dark matter in clusters of galaxies. ICMs can be detected by searching
toward M87 for ``pixel lensing'', gravitational microlensing of unresolved
stars. Dedicated observations by the Wide Field and Planetary Camera on the
{\it Hubble Space Telescope} would discover lenses at a rate $\Gamma\sim 7
f\,\rm day^{-1}$ where $f$ is the fraction of the Virgo cluster composed of
Machos (Massive Compact Objects). The only important background is lensing by
stars in M87 itself. Such self-lensing should be detected at a rate $\Gamma\sim
1\,\rm day^{-1}$. However, most of these background events should be
recognizable from their angular distribution and/or measurement of their proper
motions (which are smaller by a factor $\sim 2$ than those of ICMs). The
observations should be carried out principally in $I$, but with $V$
measurements made $\sim 20\%$ of the time in order to determine the colors of
the lensed stars. It is also possible to detect ``Class II'' lensing events
which are longer and hence for which lower signal to noise is balanced by a
much larger number of observations per event. There are $\sim 5$ times more of
these than the higher quality events. However, it is difficult to distinguish
Class II events generated by ICMs from those generated by M87 stars.
