In his book, "the coming of Tan", Riley Martin describes how he was taken on board of a huge egg-shaped "mothership" in the vicinity of Saturn. On the mother-ship he learned it was inhabited by seven different species of intelligent technological life forms, of which the Stagyinas are one.
Riley describes them as follows: The Stagyians, by any stretch of the imagination, are very ugly creatures indeed. They stand nearly six feet tall and have dark red leather-like skin draped loosely over their skeletal-like frames. The head is long and prune-like, and the eyes are tiny, black and close set.
Even aboard the craft, they both wore some kind of breathing device over their mouths, and at times you could hear their rapid shallow breathing.
I was later to learn that the Stagyians, in spite of their physical appearance, are considered to be the Pacifists even among the aliens because of their ability to store and retain vast amounts of data and recall and disseminate the same. The Stagyians hold many scientific and other brainy positions among the Biaviians, with whom they are affiliated.
I further learned that the Stagyians are the ones who perform most, if not all, of the physical examinations for the Biaviians on abductees. It is apparently the sight of these ugly but harmless beings that has caused many abductees to remain terrified of the experience, even though I am told that the Biaviians have never physically harmed an abductee, yet I can't truthfully make the same statement in regards to the Targs.
The Stagyians also communicated via telepahty. However, I could never comprehend any of what they were saying. On the other hand, neither could the Biaviians understand the Stagyians except by replaying or filtering their transmissions through some kind of electronic device.
No other authors mention this species.