The underground-dwelling species in H.G. Wells' “The Time Machine” is the Morlocks.
In Wells's 1895 novel, the Morlocks live beneath the countryside of A.D. 802,701. They maintain ancient machinery underground and reach the surface through shaft-like wells. The Time Traveller initially assumes that the gentle Eloi are humanity's only future descendants, but discovers that the Morlocks are a second, hidden branch of humanity.
The novel suggests that the Eloi and Morlocks evolved from the social divisions of the Victorian age. The leisure-loving Eloi represent an idle upper class, while the Morlocks descend from workers forced to labor underground. Their relationship is darker than a simple species rivalry: the Morlocks maintain the Eloi's world but hunt them for food.
A common mix-up is reversing the two species. The Eloi live above ground, while the Morlocks are the pale, nocturnal underground dwellers. Weena is an individual Eloi character, not a species.