Comparision of left and right upper wings.  Apart from the two blobs of green gunk, the larger of which is over a somewhat damaged area of the wing, there are other differences.  Two equivalent positions on each wing are circled.  The first shows a curved vein in one, the same vein straight in the second.  The second red circle indicates something much stranger - a cell on the wing with a rather different shape on each wing.
Derivative of work by <a href="//commons.wikimedia.org/wiki/User:Alvesgaspar" title="User:Alvesgaspar">Alvesgaspar</a>, cropped by <a href="//commons.wikimedia.org/wiki/User:Tony_Wills" title="User:Tony Wills">User:Tony Wills</a>
CC BY-SA 3.0
<a href="//commons.wikimedia.org/wiki/File:Dragonfly_June_2009-2.jpg" title="File:Dragonfly June 2009-2.jpg">File:Dragonfly June 2009-2.jpg</a>