There are lots of differences. First thing to notice is the size of the blue bands along the abdomen - barely there in billabongfly but quite extensive in Wandering Ringtail. Other differences include the colour of the upper stripe on the thorax; the billbongfly has two blue patches at the very end of the abdomen; billabongfly is smaller, etc. They are in quite different families so the differences are actually quite extensive. It is more usually a case of distinguishing Eastern Billabongfly from Common Bluetail.