ISLE OF WIGHT DISEASE IN HIVE BEES — EXPERIMENTS ON INFECTION. 205 



result obtained. On the fourteenth day of the experiment one bee was found to 

 contain one ovigerous female at 'the entrance of the tube. 



(b) By contact with dead bees. 



Before commencing these experiments, observations were made to discover how 

 long the parasites lived after the death of the host. It was found that a few female 

 mites were still capable of feeble movement on the fifth and sixth days. 



Seven of these experiments were put up in the same way as the foregoing, sub- 

 stituting newly killed bees for the living sick bees. The result in this group \v:as 

 negative. 



(c) By placing tracheal tubes containing the parasite on the thorax of healthy 

 bees. 



Preliminary observations were made on the behaviour of the mites when the 

 tubes had been dissected out of the bee. These were placed in welled slides, and 

 both sexes of the mites were seen to emerge within an hour. These wandered about 

 actively, and were occasionally seen to re-enter the tubes. In most cases the mites 

 became inert and passive within twenty -four hours of leaving the tubes. It cannot 

 be said with certainty that in any of these experiments the mites are really dead. 



Bees were now taken from a stock known to be free from infection, and tubes 

 containing the parasite were placed on the thorax near the first spiracle. Twenty- 

 four bees were treated in this manner, and were examined after twenty-four hours. 

 It was found that no infection had taken place. 



Examination of the stocks from which the experimental bees were taken, for the 

 presence or absence of the parasite, were being regularly carried out. 



It is to be clearly understood that the whole of the foregoing experiments are 

 provisional in character, and all of them, as well as others, are being repeated upon a 

 larger scale. 



From the results obtained, as far as they go, however, it appears that experi- 

 mental infection with the parasite Tarsonemus is difficult to eft'ect ; it must be taken 

 into consideration that any deviation from the normal habits of the bee host such as 

 is involved in these experiments may have a corresponding eflfect upon those of 

 the parasite. 



I wish to express my sincere thanks to Dr Rennie, both for his help and advice 

 in the preparation of this paper, and for his kindness personally whilst I have 

 worked under him. 



