256 



ECONOMIC ENTOMOLOGY 



peculiar clasping base, often several to a hair; 3^ ^5 inch long; dull 

 yellowish-white; narrow; ovoid. 



Larva. — Dr. Cooper Curtice of Washington believed that the eggs 

 were licked into the mouth and the maggots bored through the wall of 

 the oesophagus, whence they gradually made their way to the tissues 

 along the back, causing warbles. 



Miss Ormerod, of England, on the other hand maintained the 

 popular belief that the eggs were laid on the back, but Carpenter 

 of Ireland, and more lately Dr. Hadwen of Canada, have proven fairly 



Pig. 162. — The striped warble fly {Hypoderma linealum). Enlarged. {After 



Hadwen.) 



conclusively that the eggs may be laid on almost any part of the 

 body of the animal, and that the maggots bore into the skin where 

 lesions and swellings are produced. They finally make their way to 

 the back where the warbles are formed. 



Full grown maggots are greyish-white and nearly an inch long. 

 When mature they make their way out through the minute opening, 

 drop to the ground and bore an inch or so below the surface, where they 

 change to pupae. Four stages of larva; duration 9-10 months. 



Pupa. — Puparium dark brown. Duration 3-6 weeks. 



