  A large number of early type galaxies are now known to possess blue and red
subpopulations of globular clusters. We have compiled a database of 28 such
galaxies exhibiting bimodal globular cluster colour distributions. After
converting to a common V-I colour system, we investigate correlations between
the mean colour of the blue and red subpopulations with galaxy velocity
dispersion. We support previous claims that the mean colour of the blue
globular clusters are unrelated to their host galaxy. They must have formed
rather independently of the galaxy potential they now inhabit. The mean blue
colour is similar to that for halo globular clusters in our Galaxy and M31. The
red globular clusters, on the other hand, reveal a strong correlation with
galaxy velocity dispersion. Futhermore, in well-studied galaxies the red
subpopulation has similar, and possibly identical, colours to the galaxy halo
stars. Our results indicate an intimate link between the red globular clusters
and the host galaxy; they share a common formation history. A natural
explanation for these trends would be the formation of the red globular
clusters during galaxy collapse.
