APPENDIX. 115 



week, so that two weeks is about the average^time from the laying 

 of the egg to the appearance of the flies. "With four active 

 breeding months, May 15 to September 15, there will be eight, 

 generations," so that the large numbers of the flies are not sur- 

 prising. 



Of the amount of damage done by the fly, Messrs. Riley audi 

 Howard ( Insect Life, loc. cit.) say : 



The amount of damage done by the fly has been exaggerated by 

 some, and underestimated by others. We have heard many rumors of 

 the death of animals from its attacks, but have been unable to substan- 

 tiate a single case. We believe that the flies alone will never cause the 

 death of an animal. They reduce the condition of stock to a consid- 

 erable extent, and, in the case of milch cows, the yield of milk is re. 

 duced from one-fourth to one-half. It is our opinion that their bites 

 seldom produce sores by themselves, although we have seen a number 

 of cases where large sores had been made by the cattle rubbing them- 

 selves against trees and fences, in an endeavor to allay the irritation 

 caused by the bites; or, in spots where they could not rub, by licking 

 constantly with the tongue, as about the bag and on the inside of the 

 hind thighs. A sore once started in this way will increase with the con- 

 tinued irritation by the flies, and will be difficult to heal. Those who 

 underestimate the damage believe that the flies do not suck blood; but 

 such persons have doubtless watched the flies only upon the horns or 

 elsewhere, in their resting position, when the beak, is not inserted, or 

 have caught them and crushed them when their bodies contained little 

 blood. In reality, the flies suck a considerable amount of blood, how- 

 ever, and it is their only nourishment; if captured and crushed at the 

 right time, the most skeptical individual will be convinced. 



Remedies. — The following notes on remedial measures are 

 quoted from Insect Life (foe. cit.) : 



Pbeventive Applications. — Almost any greasy substance will keep 

 the flies away for several days. A number of experiments were tried 

 in the field, with the result that train-oil alone, and train-oil with a little 

 sulphur or carbolic acid added, will keep the flies away for from five to 

 six days, while, with a small proportion of carbolic acid, it will have a 

 healing effect upon the sores which may have formed. Train-oil should 

 not cost more than 50 to 75 cents per gallon, and a gallon will anoint a 

 number of animals. Common axle grease, costing 10 cents per box, 

 will answer nearly as well, and this substance has been extensively and 

 successfully used by Mr. William Johnson, a large stock dealer at War- 

 renton, Va. Tallow has also been used to good advantage. The prac- 

 tice of smearing the horns with pine or coal tar simply repels them 

 from these parts. Train-oil or fish-oil seems to be more lasting in it& 

 affects than any other of the substances used. 



