How can I see what alien types I've already captured alive in XCOM?

I stopped using the arc thrower for a while because I was getting my butt kicked and started equipping everyone with medikits to up survival rates.

But I'm in better shape now, and want to round up any alien types I never captured.

But I can't recall what aliens I've already captured to study. Is there someplace I can look to see a list without backing into it by looking at the tech I can build and looking up its pre-requisites earlier int he tree?

The Research Lab contains a list of all completed research. This includes the research item that is unlocked from interrogating aliens.

If you consult the completed research list, you should be able to determine who you still need to interrogate by process of elimination.