The original Tech Infantry tabletop role-playing game drew on two major sources: White Wolf's classic World of Darkness, and Robert Heinlein's novel Starship Troopers. The first "season" of Tech Infantry was little more than mages, ghouls, and werecreatures in power armor fighting Arachnids in subterranean bug tunnels with magick and machine guns.
Over time, though, Tech Infantry drifted further and further from its source material. By the time the play-by-email seasons started (which are the only ones we have a written record of), the story lines revolved more around inter-human political power plays than fighting the Bugs. After Season Nine, the Earth Federation collapsed and the Tech Infantry was disbanded, so Starship Troopers is less relevant than ever.
The Bugs are still out there, though, and occasionally pop up in the TI Universe. The Starship Troopers Wiki is a treasure trove of information about Arachnids, power armor, and other technology.
Here's a link to their website: The Starship Troopers Wiki