1916 



ENTOMOLOGICAL SOCIETY. 



109 



and if any treatment is to be undertaken it is absolutely necessary to know 

 when they come and go. As I have already pointed out, the statements made 

 by the European writers about the length of the season, especially for H. li/neaium, 

 are very vague. 



The following table gives a complete record of the observations. The cattle, 

 ten in number, were kept in a field directly in front of my laboratory. The 

 animals were under almost constant observation. Whenever they were seen run- 

 ning, either myself or assistant went out to look for flies. If flies were noticed in 

 the morning, then no further trouble was taken for that day. It is of course 

 possible that we may have failed to observe them on some occasion or other, but 

 this seems hardly likely, seeing that II. hovis invariably causes alarm among cattle. 



The most likely error made was in the catching of flies, but these were mainly 

 caught when thej were abundant. It may be that on one or two occasions the 

 flies which were taken would have lived over night and attacked the cattle on 

 the following day. The only dates on which this may have occurred was on. June 

 15th and 22nd. The meteorological records were kindly supplied by Mr. Moore, 

 Superintendent of the Experimental Farm. In comparing. them with my records, 

 I was delighted to find that the changes of temperature coincide almost perfectly 

 with the appearance and disappearance of the flies. 



The Seasonal Prevalence of Hypodebma bovis in 1915. 



Sunshine. 



June. 



1... 



2... 



3... 



4... 



5... 



6... 



7... 



8... 



9... 

 10... 

 11... 

 12... 

 13... 

 14... 

 15... 

 16... 

 17... 

 18... 

 19... 

 20... 

 21... 

 22... 

 23... 

 24... 

 25... 

 26... 

 27... 

 28... 

 29... 

 30... 

 July 



]... 



Hrs. 



Min. 



Rain. 

 Inch. 



Cattle quiet, no flies. 



Plies seen, cattle running. 



1 H. bovis taken 



-Cattle quiet, no flies 



Flies seen, cattle running. 



1 H. bovis taken 



Cattle quiet, no flies 



5 

 1 

 2 

 11 

 11 

 7 

 2 



1 

 5 



1 1 H. bovis taken 



15 H. bovis taken U 



D 



2 H. bovis taken 



Cattle quiet, no flies 



Flies seen, cattle running. 



11 

 1 

 3 



Cattle quiet, no flies 



1 H. bovis taken 3 



6 H. bovis taken 9 



Flies seen, cattle running 11 



2 H. bovis taken 10 



Flies seen, cattle running 



II 



II 



Cattle quiet, no flies 11 



42 

 48 

 54 

 06 

 54 

 24 

 00 



ull 

 18 

 30 

 18 

 00 

 18 

 30 

 36 

 42 



uU 

 54 



ull 

 54 

 48 

 42 

 06 

 24 

 12 



ull 

 42 

 24 

 36 

 48 



36 

 42 

 18 



.47 



(l.S 



.6 

 .35 



.65 

 ."6 



.02 

 .03 



.05 



Temperature, "F. 



Max. 



64 

 62 

 72 

 78 

 82 

 81 

 65 

 64 

 64 

 59 

 58 

 64 

 67 

 70 

 78 

 67 

 64 

 62 

 64 

 67 

 81 

 82 

 74 

 78 

 76 

 70 

 76 

 80 

 84 

 fH 



93 



89 

 84 



Min. 



48 

 49 

 42 

 48 

 50 

 52 

 47 

 46 

 51 

 45 

 46 

 51 

 50 

 53 

 55 

 51 

 50 

 46 

 47 

 45 

 43 

 43 

 46 

 46 

 45 

 47 

 46 

 43 

 48 

 49 



56 

 55 



56 



