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even when it is buried in the tissue of an animal, as long 

 as the extreme end of the body comes into contact with 

 the outer air. 



The full-grown maggot is about J-inch in length. 

 The pupa is an oval, seed-like body, brown in colour, 

 about J-inch in length. 



The life-cycle occupies about 3 or 4 weeks, divided as 

 follows : 



Egg 1 to 48 hours 



Maggot 7 10 days 

 Pupa 14 ,,21 days 



Egg-laying begins in a very short time after the 

 emergence of the adult. 



The injury to animals attacked by the screw worm 

 arises from the amount of irritation to the wounds infested 

 by the maggots, the loss of blood and the destruction of 

 tissue, and also from blood poisoning, which frequently 

 results. 



Control. In any locality where the screw worm occurs 

 in numbers, great care should be taken to prevent the access 

 of the fly to wounds, sores or exposed tender tissues on all 

 domestic animals. This can be done by prompt treatment 

 with some substance which will repel the fly, or will make 

 it impossible for the eggs to be laid. After the maggots 

 have actually infested the animals, the wounds should be 

 carefully cleaned, all the insects removed and the wounds 

 dressed. 



The following substances have been tried and have 

 given good results : 



Fish oil, used alone, serves to keep off the flies and pre- 

 vent egg-laying. It may be used in a mixture with any of 

 the following, for a dressing. 



Carbolic acid. Used to kill maggots, and to cleanse and 

 disinfect wounds. If used alone, it should be applied with a 

 feather. Mixed with sweet oil, its action is not so severe, 

 and it may be used more liberally. 



Jeyes fluid may be used in the same manner as car- 

 bolic acid. It may be diluted with water to make a disin- 

 fectant wash. 



A mixture of Jeyes fluid 3 parts and Friars balsam 2 

 parts, or carbolic acid 1 part and Friars balsam 2 parts, is 

 also very efficient, 



