FOREST FLY. 



77 



two attacks are popularly confused. The difference is 

 easily shown hy an anatomical demonstration of the 

 maggots in the nostrils in one case, and the hydatid- 

 infested brain in the other. 



There is another small division of Flies which infest 

 horses, sheep and other animals, also birds, which are 

 remarkable for their peculiar method of increase. 

 They do not lay eggs, but feed in maggot state on 

 secretions within the abdomen of the female Fly until 

 they are full grown. Then they change to the pupal 

 state, and are produced either in this condition, or 

 quite immediately on the point of changing to it, 

 whence this division of Flies takes the name of 

 pupipcnri. 



Fig. 61. — Forest Fly, nat. size and magnified. Egg-like pupa and 

 toothed claw, also magnified. 



The Forest Fly {Hipijohosca equina), which infests 

 horses and cattle, and is especially common in the 

 New Forest in Hampshire, may be taken as a type of 

 the division. The figure above shows the egg-like 

 pupa, and also the peculiar toothed claw. The main 

 colours of the little Fly are brown or black, varied 

 with some shade of yellow. It causes irritation both 

 by blood-sucking, and by creeping, which it can do 

 backwards, forwards, or sideways with great nimble- 

 ness, on the parts of the animal especially preferred 

 for infestation. 



