ENTOMOLOGY

206 SANITARY ENTOMOLOGYeggs and get rid of larvre. Clipping of the hair on the legs has alsobeen recommended but is not entirely satisfactory. Dove has experimentedwith certain ·halter devices for the protection of horses in pasturesand also with various types of guards to be used on horses illharness to prevent the attack of the nose fly (fig. 40). In the first casehe used a halter, from which is suspended a box-like arrangement thatcovers the nose when the horse has its head up, but permits of grazingand drinking. A canvass extends back under the jaw to prevent depositionof eggs by the throat bot, and of course the covering of the mouthprevents the ingestion of eggs of the common bot. The main difficultyhas been the production of a durable device of this kind. The nose flyattack is best prevented by a rectangular piece of belting being suspendedfrom the bit rings immediately below the lips, when horses are,at work.The internal treatment of infested animals with carbon disulphidehas heen found to be very efFective if properly done. Three three-dramdo~s at hourly intervals are given in capsules succeeding a period ofstarvation and followed by a purgative.Pretention of Attack in Man.-The reduction of the number of batsby treatment of the lower animals will greatly reduce the chances of infestationin man. Care should be taken not to ingest eggs or larvre,,"hen infested horses are being clipped or groomed.PREVENTION OF ATTACK BY OTHER FORMs.-This group includesthose species accidentally infesting man such as the IHuscids MWlcadomestica, and Muscma spp., Fannia, and Syrphus flies.Destruction of Breeding PlaceB.-Since most of these forms arebreeders in excrementitious matter and decaying vegetation, the propercare of manure of all kinds is important. This has been discussed in otherlectures. Since some of the species, especially }