REPELLENTS FOR PROTECTING ANIMALS FROM FLIES. 7 



The author states that the administration of potassium tellurate in 

 all cases failed to protect animals from flies. 



It would therefore seem likely that this internal remedy is not 

 efficacious. If it or any other internal remedy were found efficacious, 

 it is doubtful whether it could be administered to dairy cows with- 

 out imparting an odor to the milk. On the whole, therefore, the use 

 of internal remedies seems to be an extremely unpromising means of 

 repelling flies. 



EXTERNAL REMEDIES FOR REPELLING FLIES. 



There are almost innumerable homemade and proprietary ex- 

 ternal remedies for repelling flies. They contain various substances 

 that are distasteful to the insects. Many of them contain strongly 

 odoriferous ingredients that have a repelling influence on flies. The 

 qualities to be sought in a satisfactory repellent are: Absence of 

 toxic and other detrimental properties when applied externally to 

 animals; a marked repellent action on flies; and a duration of this 

 action for a reasonable length of time. A common defect of many 

 otherwise rather good repellents is the very short period during 

 which they are effective. Some repellents are undoubtedly toxic 

 and must be used with care. 



METHODS OF APPLYING REPELLENTS. 



Repellents as a rule are in the form of liquids and may be applied 

 by means of a dipping vat, a pail spray pump, an atomizer such 

 as that commonly used in gardens and greenhouses for applying 

 insecticides to plants, or b}^ means of a rag or a paint brush. The 

 method employed necessarily depends to a very large extent on the 

 number of animals to be treated, the physical character and toxicity 

 of the preparation, its cost, and the individual preference of the 

 farmer or stockman. Some preparations, either because of their 

 cost or their toxicity, or for some other reason, are not adapted for 

 use in a dipping vat or for application by means of a spray pump. 

 Others may be applied by any one of the methods mentioned. 



Marlatt (1910) describes a special splash board for vats, devised 

 by J. D. Mitchell. By means of this board the splash caused when 

 the animal plunges into the vat is thrown back into the vat in the 

 form of a spray and many of the flies are wetted and carried down 

 with the dip. It is said that with vats equipped with such splash 

 boards from 75 to 80 per cent of the hornflies are killed. 



EFFICACY OF PROPRIETARY REPELLENTS. 



Lindsey (1903), at the Massachusetts Agricultural Experiment 

 Station, tried out 10 proprietary fly repellents. He found that four 

 were quite satisfactory, four others were less satisfactory, and two 



