Grotto of Formigans

This truly scarifying science-fiction novel is set in Zaïre, and is about a black man from America, Maynard Griggs, who is doing anthropological research in some of the native tribes in the jungle. He meets a Cuban woman terrorist named Consuela who has crashed in her helicopter after going off course from Angola, and they get lost in the jungle and get overwhelmed by hordes of small vaguely humanoid creatures who live in tunnels deep in the ground, like ants. They are the Formigans of the title, but how they originated aeons ago is not entirely clear. They are very tall and very thin, with tiny, baby-like arms and legs and great saucer-like eyes, and a human can easily kill one with his bare hands; but hundreds of them can overwhelm you in the end, after you are exhausted from struggling. They have pale white skin that cannot stand light or water, and give off an ant-like smell of formic acid; they are the Formigans of the title, and are organized like ants with specialized castes and a hive-like social structure. They are semi-intelligent, and form a kind of group mind. The feeling seems to be that the Formigans are not very intelligent as individuals, and in fact seem rather zombie-like, but that their group mind is intelligent. They are ruled by a bloated, immobile Queen who is telepathic with other Formigans (and with humans too, provided she can look into your eyes), and her name is JEH, and whatever other Formigans do or know, she also knows about. The book is a convincing portrayal of a truly alien species with alien ways of thinking. The two humans are not threatened in any way at first, but wonder uneasily what the Formigans want of them. Although their lives do not seem to be at risk, an appalling truth eventually becomes manifest to them. The Formigans are very interested in seeing that their two hapless captives do not escape back to ground-level again. Not only do they not want the humans to make their existence known in the world, but they also have their uses for humans. The humans are never in any danger of dying at the hands of the Formigans, however; they are far too valuable to let die. Indeed, they are impregnated with a special fungus that, amongst other effects, makes them almost immortal; but that may not be a blessing if you are stood immobile like a pillar in a fungus farm for hundreds of years. The two humans meet others who suffered this fate many decades ago, who are still alive and conscious in one of the caves, although with fading eyesight. This fate of unlucky humans who are captured by the Formigans is the main thing that is horrifying about this novel. Indeed, it is one of the most horrifying novels I've ever read, and is one of that rather small group of novels that persuade readers that far worse fates than death can be conceived of. (Run-of-the-mill horror stories, on the other hand, simply work variations on violent ways of dying - but that death itself would be an escape from the violenc