Supergirl makes her first appearance with the Legion in their Adventure Comics run, in issue 313 (Oct 63) in a story that sort of features the female Legionnaires, in so far as they all come down with a mysterious disease.
Saturn Girl,Phantom Girl,Triplicate Girl, Shrinking Violet and Lightning Lass fall ill from the Crimson Virus, as does Night Girl from the Subs, and are taken to Quarantine World.
Satan Girl shows up and claims responsibility for the disease, and that she intends to head to Quarantine World and kill the women. Rather than pursue her, Sun Boy appoints Supergirl temporary leader and sends her off to battle Satan Girl, while the rest of the guys stay safely on Earth. Cowards.
Anyway, Supergirl is mystified by Satan Girl, who not only is equally powerful, and immune to kryptonite, but also seems to know everything about Supergirl.
Supergirl heads back to Earth, and convinces the boys that they need to move the girls to a secret location. Bouncing Boy once again proves himself extremely useful.
As Satan Girl’s powers cannot affect animals, Supergirl assembles the Legion of Super-Pets and has them take down the villain.
Ultimately, it turns out Satan Girl was an evil duplicate of Supergirl, created by red kryptonite she was exposed to on her trip to the future. Satan Girl does make one further appearance, as part of the End of an Era storyline in the early 90s.
Not the greatest Legion tale by Edmond Hamilton, but it does have Curt Swan art. And I’m a sucker for the Super-Pets.
After giving Pa Kent a Father’s Day present, Clark uses a mind-probe machine to remember how the day was celebrated on Krypton.
We get to see Jor-El taking baby Kal to the family tomb, with its row of statues commemorating great heroes of the El family. Superboy seeks out the statue and in space, and wouldn’t you know it, finds it intact and floating around, along with a box of curious objects.
It’s much more of a challenge to approach the poisonous statuary group than to figure out the purpose of the objects, which clearly fit into the hands of the statues.
Superboy succeeds by covering the whole thing with lead, and we (and he) learn that the El family included a great explorer, inventors, the writer of Krypton’s constitution and a renowned architect.
This statue group would appear occasionally, as would some of the men pictured. Primarily, it would be the basis for part of the Krypton Chronicles mini-series.