Rough Patch

Military patch.

Found in "Pocket Dictionary of the French and English Language" by J.E. Wesseky. Published by Doubleday, 1929.

If anyone knows what this patch represents, leave a comment. I was unable to find it online.

Update - Crossett Library was kind enough to find out. It's a 4th Air Force.

Update 2 - Phoebe (via Facebook) has a bit more info:  

WW2 era US Army Air Corps 4th Air Force. They were the defence force for the Southwestern and Lower Midwest US HQ'ed out of March Field in California.

-Click to enlarge photos-