how to append an element between two elements

I have a List

     <ul>
           <li id="lst1"> list item One</li>
           <li id="lst2"> list item two</li>
           <li id="lst3"> list item three</li>
           <li id="lst4"> list item four</li>
           <li id="lst5"> list item five</li>
     </ul>

and i want to append an item between (not inside) "lst2" and "lst3" i don't know how using jquery. Thanks.