[jQuery] LI:last of submenu's

[josb...@gmail.com]

I don't want background-image's on all the last list-items of a
submenu.
I use this code but it only apply the edit to the last submenu.
$('ul#sidebarmenu1 ul li:last a').css('background-image', 'none');
How can i apply this to all submenu's?
My HTML (generated by CMS):
<ul class="menu" id="sidebarmenu1">
    <li class="parent item65"><a href="#"><span>Link 1</span></a>
        <ul>
            <li class="item73"><a href="/link/"><span>Sublink 1</
span></a></li>
           <li class="item77"><a href="/link/"><span>Sublink 2(*****)</
span></a></li>
        </ul>
    </li>
    <li class="item66"><a href="/link/" target="_blank"><span>Link 2</
span></a></li>
    <li class="parent item65"><a href="#"><span>Link 3</span></a>
        <ul>
            <li class="item73"><a href="/link/"><span>Sublink 1</
span></a></li>
            <li class="item74"><a href="/link/"><span>Sublink 2(*****)
</span></a></li>       </ul>
    </li>
</ul>