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obvious to the onlooker. But, prior to the discovery 

 of Tarsonemus woodi as a pathogenic endoparasite of 

 the tracheal system of the bee, this was the only indi- 

 cation. Only such cases as reached this chronic condition 

 were recognised. This has given in the minds of the 

 uninitiated an erroneous idea of the malignancy of the 

 infestation. 



I have no reason to minimise the gravity of this 

 malady. But we have only to remember the com- 

 plexity of factors and varying conditions under which 

 the parasite seeks to maintain its existence, to recognise 

 the absurdity of the claim that if this organism is 

 present in a particular colony of bees, it ought to 

 destroy such, and of the argument that if it does not, 

 it cannot be the cause of failure of other colonies in which 

 its presence and pathogenic character are manifest. 

 Competent scientific observers will readily realise that 

 in degree of original infestation, immediate environ- 

 ment, the breed or race of bee, age of queen, size of 

 colony, season, climate, beekeeper, each colony presents 

 to the invading parasite a complex of factors which, in 

 the struggle for existence may be expected in a propor- 

 tion of cases to prove effective either in its elimination 

 or in the keeping of it at a relatively harmless level. 



It must be recognised, therefore, that the presence 

 of a proportion of acarine infected bees in a colony, 

 so far as that colony is concerned, is not a sure indica- 

 tion of more or less immediate disaster. It is an un- 

 favourable factor, certainly, but counter to it there 

 may be a number of favourable ones. 



