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BULLETIN 



OF THE 



Ohio Agricultural Experiment Station 



Numbkr 356 Fkbruary, 1922 



SOME PESTS OF OHIO SHEEP 



DON C. MOTE* 



/ 



SHEEP BOT FLY 



Symptoms. — The action of sheep when attacked by the bot fly 

 is familiar to every farmer and flockmaster. At the appearance of 

 the fly, the sheep shake their heads and strike the ground violently 

 with their fore feet. Lowering their noses to the ground, they run 

 away from the spot in an attempt to shake off or dodge the fly. 

 During the heat of the day, the sheep may crowd together with 

 their noses held close to the ground or close under each other in an 

 endeavor apparently to prevent the fly from striking them upon the 

 nose. 



Description of Insect. — The adult fly is said to look something 

 like an overgrown house fly. Although larger than the house fly, it 

 is very difficult to see, and still more difficult to catch when flying. 

 Notes on the life history of this fly and its habits in Ohio are not 

 complete. However, the Ohio Station has in its parasite collection 

 specimens of grubs in various stages of development, which throw 

 some light upon this subject. 



Minute larvae measuring one-sixteenth and five-sixteenths of 

 an inch in length were found in the nasal cavities of sheep on Sep- 

 tember 26, 1916, at Wooster. Larvae of about the same size were 

 found crawling up the nasal passages of sheep examined at Carpen- 

 ter, Ohio, on November 6, 1916. From the size of these specimens 

 it may be inferred that the fly is prevalent and depositing eggs or 

 living larvae in late summer. 



The minute larvae crawl up the nasal passages to the frontal 

 sinuses — cavities located between two plates of the skull and lying 



*State Entomologist, Phoenix, Arizona. Formerly Parasitologist, Ohio Experiment 

 Station. 



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