strange mannerism of .each()

strange mannerism of .each()

hey guys
this is not really a problem because i've found another way but i want to understand jquery properly.
i have following code structure:
  1. <div id="a">
  2.       <div class="b c"></div>
  3. </div>
when i trigger
  1. $( "#a > .c").each(function( index ){ //...});
it selects correctly all elements with class='c' under div #a.
If I write instead:

  1. $( "b + c").each(function( index ){ //...});
it triggers all elements with class='c' under div #a except the first element.
Do you know why this is like that? Thanks in advance!