  High energy cosmic ray experiments have identified an excess from the region
of the Galactic Plane in a limited energy range around $10^{18}$ eV (EeV). This
is very suggestive of neutrons as candidate primaries, because the directional
signal requires relatively-stable neutral primaries, and time-dilated neutrons
can reach Earth from typical Galactic distances when the neutron energy exceeds
an EeV. We here point out that if the Galactic messengers are neutrons, then
those with energies below an EeV will decay in flight, providing a flux of
cosmic antineutrinos above a TeV which is {\it observable} at a kilometer-scale
neutrino observatory. The expected event rate per year above 1 TeV in a
detector such as IceCube, for example, is 20 antineutrino showers (all flavors)
and a $1^\circ$ directional signal of 4 $\bar \nu_\mu$ events. A measurement of
this flux can serve to identify the first extraterrestrial point source of TeV
antineutrinos.
