I photographed this bee close to a small stream on the outskirts of Bandung, west Java, Indonesia, 13-11-2011. A fairly accurate estimation of it's length is 36mm, as I returned to the site with a measuring rule and a print.
I have tried Google searches and was not expecting to have problems with such a large and distinctive bee, but came up blank.
Really hoping that you can help me.
It does look similar and I am seeing a lot of red tailed bumble bees where I am now, Storeton woods, UK. But, this bee was frighteningly large and there are some big bees around in Indonesia.
It is a ground dweller, as the first time I saw this bee, was coming out of a hole in the ground at the base of a tree.