ENTOMOLOGY

SANITARY ENTOMOLOGYNemathelmimthcs: Nematoda: AncylostomidacAncylostoma duodenale D'ubini, cause of HOOK WORM disease ofman, has been found in the egg stage in house fli(!s, M UIIca domestica, byShircore (1916) in British East Africa, and it is therefore possible thatthe eggs may be placed on food, in which the hook worm larva couldhatch and be directly conveyed into the body with the food. No developmenttakes place in the flies. .Necator american~ Stiles, the American HOOK WORM, was collectedin the egg stage in the intestines of Limosilla punctipenlftis in St. Luciaby Nicholls (191~). Galli-Valerio (1905) found that flies could carryon the surface of their bodies not only the eggs but also the larvreof this worm.•N emathelmintMs : Nematoda: TrichosomidaeTrichiuris trichiura (Linnaeus), the WHIP WORM of man, was collectedin the egg stage by Shircore (1916) in British East Africa in theabdomen of Musca domcstica and by Nicholls (1912) in St. Lucia in theabdomen of Borborus punctipennis (Limosina), and the latter succeededin feeding Musca domest.ica on the eggs. It probably does not requirethe flies as immediate hosts, but is undoubtedly distributed in this manner.Thus to the already long list of serious diseases in whose spread thenon-blood-sucking flies may play some part we may now add ~og cholera,poliomyelitis, amoebic dysentery, Lamblian dysentery, Oriental sore,surra, murrina, yaws, purulent ophthalmia, trachoma, the fat-tapewormof cattle, the fowl tapeworm, bilharziosis of man, the stomach wormof horses, equine granular dermatitis, human ascariasis (not normalmethod), equine pinworm, pin itch, two hook worms, and the whip worm,and possibly also smallpox, measles and scarlet fever.We found that the bacteria were only mechanically carried by theflies, except in the case of Bacillus anthracis. A~ong the protozoa alsothose organisms parasitic in vertebrates all seem to be mechanicallytransmitted. The various parasites mentioned, however, pass completelife cycles in the body of the fly. Among the worms, however, there arecases of external mechanical carriage, transmission of eggs throughthe intestinal canal, retention of the egg from larva to adult fly (Ascarislumbricoides), and also cases of the fly serving as an intermediate host(Choanotaenia infwndibulum, and Habronema spp.). The last namedworms are the only organisms known to be transmitted by the fly whichwork for\vard into the proboscis for transmission at time of feeding.A bibliography of the works cited in the lecture follows: