Adventure Comics (1938 1st Series) #373 FN
Published Oct 1968 by DC.
Cover art by Neal Adams. Intro of the Tornado Twins in The Tornado Twins!--Tales of the Legion of Super-Heroes, script by Jim Shooter, pencils by Jim Shooter (layouts only) and Win Mortimer, inks by Win Mortimer; The Tornado Twins use their super-speed powers to upstage the Legion, but it was only a publicity stunt for Flash Day. 36 Pages, Full Color. Cover price $0.12.