css dropdown menu showing the images on every child elements on hover

[othmam]

I am using WordPress twentyeleven theme and developing my custom theme. The live demo of the site can be seen here. In that site you can see there are two types of menus. On the left and another one in the right side. In the right side menu you can see there is a drop-down menu.Here when you will hover on the parent menu drop down box will come but there is one problem with this. When you will hover on the parent menu the drop-down menu can be seen but with the arrow on the right side. So here I want there should be no arrow images on the sub menus when I will make hover on the parent menu. Can someone tell me how to do this?I am really stocked with this point.