a retarded question. *is ashamed*

I just want to make sure I'm not mixing things up. So far as I understand, a "columbian boa" is always a "columbian red tail boa". Is this correct, or are they two different snakes? (or for that matter, more than two. ex: a columbian boa could be any of the multitude of snake species that come out of columbia.)

...I cant believe I'm asking this, but I've looked all over the web and the snakes are always referred to as either a "columbian" or "columbian red tail" and the pictures always have a greyish or brown snake with a tail covered in red saddles. This is why I'm confused.