1LT C.W. Mahannah's P-51B/C from the 23rd FG in the CBI. Not sure what is under the wing, at first I thought it was bazooka tubes with some sort of bracing but I found a better picture showing the front angle more and those are definitely not bazooka tubes. It kind of looks like a M-69 incendiary cluster bomb without the outer casing.
Here's a better picture of the Iowa Belle showing whatever is mounted under the wing.

This is a diagram of the M-69.

You might get a more definitive answer in this forum thread. The OP is the grandson of 1LT. C.W. Mahannah's that was looking for more info about his grandfather and where I got the other picture from.
http://forum.armyairforces.com/Iowa-Belle-m153290.aspxack-ack