BOT-FLIES. 209 



they do by throwing off their old skins and replacing them 

 with smooth and lancet-shaped new ones. The nomadic 

 males are found not only in the nasal cavity, but also in the 

 pharynx and larynx, while the females are less active. They 

 are shown in position in fig. 173. 



Generally speaking this parasite is not as common in 

 the United States as it is in Europe. It has been found in 

 the nasal cavities of the horse, mule, sheep, goat, hog and 

 man. The actual and most natural hosts are the dog and 

 the rabbit. If we prevent our dogs from eating the entrails 

 of rabbits, sheep, etc., and do not permit them to visit 

 slaughter-houses, there is little danger of an infection. To 



Fig. 173. — Three parasites in position in head of dog. 



remove such parasites an injection of dilute ammonia, ben- 

 zine, etc., is used; but in case of a valuable animal a veterin- 

 ary surgeon should be consulted. Dogs infested rub their 

 noses quite often, sneeze frequently, are easily excited, and 

 become angry and bite. If numerous in the internal organs 

 the parasites may cause death. The mature parasites cause, 

 in man, bleeding of the nose, violent catarrh, and intensive 

 headaches; those encysted in the liver cause other serious 

 disturbances, and if they migrate, bleeding of the lungs, in- 

 flammation, and even death. Another species of Five- 

 mouths is very common in Egypt, where it is found encysted 

 in the livers of negroes. 



Children should never be permitted to kiss dogs! 



B. BOT-FLIES. GAD-FLIES. 

 ( (Estridm) . 

 The flies that belong to the above family are only para- 

 sitic in their larval state; the inactive pupal state is passed 



