Based on Coude spectra obtained with the 2.24-m telescope at MKO, we d
erive a map of the surface distribution of helium for the B9p Si star
CU Vir. The helium abundance varies by more than one order of magnitud
e over the surface of this star and is concentrated in one large spot
and a second, less pronounced, spot. This pattern is in anti-phase to
the silicon surface distribution and is similar to what we have found
for ET And, which is another Si-star. We compare our observed equivale
nt width measurements and synthetic ones, which we have derived from o
ur map, with previously published data and can corroborate the long-te
rm stability of the spots. CU Vir is the second CP2 star, for which a
helium surface map is available.