Captain America #172 Apr 1974
The original X-Men appear in "Believe It or Not: The Banshee!"
After escaping from Moonstone and a police manhunt, Captain America and the Falcon follow a lead
and hitch hike to Nashville, Tennessee to investigate Moonstone's background further.
In Nashville, they literally bump into the Banshee who mistakes them as criminals looking to incarcerate or kill him.
The two battle and the Banshee incapacitates the duo thanks to his shrill mutant powers.
However, the mutant Cyclops intervenes and also spars with the Banshee.
The Banshee also knocks out Cyclops with his powers and flees the scene.
Suddenly, Captain America and the Falcon are levitated away. They find that this has been done by the mutant Marvel Girl.
Marvel Girl deposits Captain America and the Falcon by her mentor Professor X, who informs Cap and Falcon
that he believes his investigation of missing mutants and Captain America's problems with Moonstone are related.
Script by Mike Friedrich (plot assist) and Steve Englehart,
pencils by Sal Buscema,
inks by Vinnie Colletta