Q:

jQuery - Remove border from preceding sibling element

I am trying to remove the border-bottom on the sibling above the element that is hovered over on the menu. I do not know if I am using the wrong function or if it is some other issue. Thanks for any feedback.
jQuery:
jQuery(document).ready(function(){
  $('#nav_1487666 li a').mouseover(function(){
      $(this).prev().css("border-bottom", "none");
  });
});

HTML:
<ul id="nav_1487666">
    <li><a href="/index">Home</a></li>
    <li><a href="#">About</a></li>
    <li><a href="#">Landscaping</a></li>
    <li><a href="#">Irrigation</a></li>
    <li><a href="#">Porous Pave</a></li>
    <li><a href="#">Demo Dumpsters</a></li>
    <li><a href="#">Other Services</a></li>
    <li><a href="#" onclick="return false;">Lawn Care</a></li>
    <li><a href="#" onclick="return false;">Contact</a></li>
</ul>

A:

Change 
$(this).prev().css("border-bottom", "none");

To 
$(this).parent().prev().css("border-bottom", "none");// To remove border from li

or 
$(this).parent().prev().find('a').css("border-bottom", "none");// To remove border from a

