MYSTERY MEN #3, October 1939 sees the Beetle return for his third adventure, again a 4 pager by Charles Nicholas.
More changes are being made to his costume, as Nicholas feels out what is working and what isn't. The costume is basically the same as last outing, but now he has a dark eye mask. The belt is now colored yellow (although miscolored in a panel or two).
Police chief Burke makes his appearance here as well, plus an as yet un-named police commissioner.
The theme of startling the bad guys with a live blue bug, and leaving a calling card continues.
This story will be reprinted in BLUE BEETLE #1.