Stars over Stars — K.D. Wentworth

Raised by a human, Heyoka Blackeagle thinks like a human, even if he is a typical hrinn--seven feet tall, covered with fur, retractable claws. In the war against the insectlike flek, Heyoka distinguished himself in the Ranger Corps. Now, on a planet from which the flek have been driven, he's leading a group of humans and hrinn, trying to prove that hrinn can make proficient rangers in spite of their disdain for following orders.

Then a hidden, fully functional flek stargate is found, ready to transport flek hordes. And word comes of a flek advance. The planet must be evacuated, but rather than abandon his team in the jungle, Heyoka stays behind, only to find that his human partner Mitsu, once a flek POW, is hallucinating, seeing nonexistent flek. And then the real flek arrive. . . .