introduction of rats, the spread of Rhodes grass (Chloris gayana) and fires are possible reasons for their scarcity. Two species are currently listed as endangered and critically endangered by the IUCN Red List, Delosia ornata and Nocticola gerlachi. Both cockroaches have a restricted distribution and are threatened by habitat loss and rising sea levels. Only 600 Delosia ornata adults and 300 nymphs are known to exist, and these are threatened by a hotel development. No action has been taken to save the two cockroach species, but protecting their natural habitats may prevent their extinction. In the former Soviet Union, cockroach populations have been declining at an alarming rate; this may be exaggerated, or the phenomenon may be temporary or cyclic. One species of roach, Simandoa conserfariam, is considered extinct in the wild. Cultural depictions Cockroaches were known and considered repellent but medicinally useful in Classical times. An insect named in Greek "σίλφη" (silphe) has been identified with the cockroach, though the scientific name Silpha refers to a genus of carrion beetles. It is mentioned by Aristotle, saying that it sheds its skin; it is described as foul-smelling in Aristophanes' play Peace; Euenus called it a pest of book collections, being "page-eating, destructive, black-bodied" in his Analect. Virgil named the cockroach "Lucifuga" ("one that avoids light"). Pliny the Elder recorded the use of "Blatta" in various medicines; he describes the insect as disgusting, and as seeking out dark corners to avoid the light. Dioscorides recorded the use of the "Silphe", ground up with oil, as a remedy for earache. Lafcadio Hearn (1850–1904) asserted that "For tetanus cockroach tea is given. I do not know how many cockroaches go to make up the cup; but I find that faith in this remedy is strong among many of the American population of New Orleans. A poultice of boiled cockroaches is placed over the wound." He adds that cockroaches are eaten, fried with garlic, for indigestion. Several cockroach species, such as Blaptica dubia, are raised as food for insectivorous pets. A few cockroach species are raised as pets, most commonly the giant Madagascar hissing cockroach, Gromphadorhina portentosa. Whilst the hissing cockroaches may be the most commonly kept species, there are many species that are kept by cockroach enthusiasts; there is even a specialist society: the Blattodea Culture Group (BCG), which was a thriving organisation for about 15 years although now appears to be dormant.