80G TKANSACTIONS OF SUB-SECTION F 



FliTBAT, SEPTEMBER 4. 



The following Papers were read : — 



1. Discussion on Breeding and the Relation of Modern Theories of 

 Heredity to the Problems of the Stock Raiser, 



(i) The AjJjMcation of the Mendelian Theory to Practical Problems. 

 By Professor W. Bateson, F.R.S. 



(ii) Experimental Breeding Farms. By W. Heape, F.R.S. 



(iii) Mendelism and the Elucidation of Live-stock History. 

 By Professor J. Wilson. 



2. Some Irish Experiments on Warble-flies. 

 By Professor Geo. H. Carpenter, B.Sc, M.R.I.A. 



For the past four years experiments have been carried on by the Irish 

 Department of Agriculture as to the life-history of the warble-flies and the ettect 

 of the commonly accepted means for checking their attacks on cattle. In January 

 of this year a first report of these experiments was published in the Department 

 'Journal 'by the writer and Mr. J. W. Steen. The experiments were for the 

 most part carried on at Ballyhaise, co. Cavan. 



The most important practical result of the experiments has been to show the 

 iiselessness of dressing cattle either with carbolic ' dip,' oil and tar ' smear,' or 

 parafKn emulsion with the object of preventing egg-laying. For example, six 

 yearlings were smeared all over every day from May till September 1906. In 

 1907 they showed warbles averaging over 30 per beast. Four calves sprayed 

 all over daily during the same period showed an average of 15 warbles per 

 beast the next spring. The average number of warbles on untreated animals at 

 the same time was 31 for heifers and 11 for calves. 



In the spring of 1 907 a systematic squeezing-out and destruction of maggots 

 was therefore set on foot : 2,090 maggots were obtained from 194 head of cattle 

 on the Ballyhaise farm, an average of nearly 11 per head. The good effect of this 

 operation has been strikingly shown in the sipring of the present year, when from 

 166 head of cattle only 694 maggots were obtained — an average of 4'2. Equally 

 instructive is the fact that five cows grazed on the outskirts of the farm, and 

 therefore open to the attacks of flies from the surrounding country, had an average 

 of 16 warbles per beast, while 94 cows grazed near the centre of the farm had an 

 average of only 3 warbles per beast. 



Observations show that the flies lay their eggs usually on the legs, very rarely 

 on the backs of the cattle. During the summer of 1906 six calves were muzzled 

 by day and tied up between stakes at night so as to prevent them from licking 

 themselves. All but one of these had warbles in the spring of 1907, whence it 

 was surmised that the maggots may gain entrance through the skin, and not, as 

 is now generally believed to be the case, through the mouth. During the summer 

 of 1907 two calves were muzzled and tied, with additional precautions. These 

 were the only two calves on the farm that as yearlings are entirely free from 

 warbles this spring (1908). It is likely, therefore, that the protection from 

 licking in the 1906 experiments was in some way incomplete. During the present 

 summer six calves are being again treated in this way, and it is hoped th.at the 

 method of entrance by the mouth will thus be conclusively tested. 



Hypoderma bovis seems to be far commoner in Ireland than 77. lineata. In 

 both species the interval between the emergeuce of the maggot from the beast's 

 skin and the appearance of the fly is about seven weeks. 



