[electromagnetic]

It's the internet, if you don't start adding random i's to words, people will think you're new to the place. Don't forget the Viri, or even Virii.

[jonshea]

Plurals of Latin / Greek words used in English: http://alt-usage-english.org/excerpts/fxplural.html One of my favorite pages.

[scythe]

I believe the proper Latin phrase, to evoke appropriate pretension and bravado, would be prima facie.