Is there a way to change the category links on the front page from pointing to index.html to just the directory name.

Example: lets say I have a category on Cats and another on Dogs.

The links on the front page will go to:
http://www.mysite.com/Cats/index.html
http://www.mysite.com/Dogs/index.html

I would like them to just point to the directory like this:
http://www.mysite.com/Cats/
http://www.mysite.com/Dogs/

Thanks in advance for your help.