Yeah, yeah, yeah, I'm late
I had noticed the note of the Aliens thing, and I foudn this of interest. Yaujta. The Predator. The settign for the Yaujta is present day, and considering they live for millenia, is is feasable they still exsist. And as proven by the Alien Versus Predator comics, and movie, the Insect would have been in existance as well.
What made me think of these are a couple websites I found while searching the web for interesteing Yaujta pictures. The first one is the most in-depth Yaujta site you will ever find, including information on the Insect and the US Marines in the movies and comics as well
http://www.geocities.com/gunsandgod/ The second actually presents a plug-in for the Yaujta as a Monster Race, a Classable Monster race, both a stat block like out of the various compilations of MOnsters, and as a character races as well.
http://www.serenadawn.com/Alien-Plug-In-Predators.htm
The second set of people, also made on for the insects, from Face Huggers to Drones for Non-Class Avancement Monster races. Although, I kinda lost it from my favorites list, so sorry.
{edit: Fixed a rather embarassing typo . . . }
Kristine