ON ISLE OF WIGHT DISEASE IN HIVE BEES— ETIOLOGY. 749 



At the middle of September the stock' appeared well, apart from a shortage of 

 stores. Further at this date Nosema was still present. 



In the course of the summer, bees of this stock were periodically examined 

 between 17th June and 27th September for the presence of Tarsonemus. In all 

 one hundred and fifty-six bees were tested and on only two occasions, namely upon 

 20th August and 27th September, was Tarsonemus found. In each case only one 

 bee was found infected. This and a preceding stock (No. 61 ) were obtained from 

 the same apiary and have stood together, but a little way apart from the other 

 stocks, during the period of observation. Several of these other stocks in the 

 same apiary were at this time suffering from Isle of Wight disease. At the end 

 of October a sample of thirty-five bees was taken off the frames, and all were found 

 free from Tarsonemus. 



W. No. 2. — This stock, on 4th August, headed by a young queen, appeared 

 normal and in good condition. There were no visible grounds for suspecting 

 infection. Of twelve bees taken at this date, three were found harbouring 

 Tarsonemus. 



On 6th September the bees were covering most of the frames, and there was a 

 good amount of sealed brood and eggs in the inner frames. There were no signs of 

 disease. At 20th September one crate of sections honey was obtained and about 

 20 lbs. of stores were left in the hive. At this date fourteen bees were taken at 

 random, and of these twelve showed infection with Tarsonemus and two were clear. 



At the end of October, of twenty-eight bees supplied, twenty-three were found 

 infected. 



No.. 24. — This was a nucleus of five frames of Italian bees obtained upon 11th June. 



Twenty -two bees were examined at this date and these were found to be free 

 from Tarsonemus infection. A fortnight later thirty-two bees were examined and 

 one bee only was found containing this parasite ; everything appeared normal with 

 the stock. Throughout the summer the stock prospered only moderately well. In 

 the first week of September twenty-three bees were taken at random, and of these 

 one only contained Tarsonemus. The stock has yielded no surplus stores and there 

 has been no indications of disease. Nosema apis is not present in the stock and the 

 apparent weakness cannot be attributed to it or to Tarsonemus. 



Twenty-two bees were examined, and all found negative, on 29th October 1920. 

 It would, therefore, appear that although Tarsonemus was present in the stock as 

 early as the 25th June, there was no apparent increase in the incidence of infection 

 as late as the end of October. 



Re. No. 1. — This stock was brought to Aberdeenshire in the month of June 

 from Caithness-shire. The bees, headed by a 1919 queen, were bred in this district 

 in an apiary which had existed for many years and has had no experience of the 

 disease. Thirty bees were examined on 3rd July and all were found free from 

 Tarsonemus infection. The bees were placed in an area which has not been free 



